The activities of transcription factors （TFs） require interactions with specific DNA sequences and other reg- ulatory proteins. To detect such interactions in Arabidopsis, we developed a high-throughput screening sy...The activities of transcription factors （TFs） require interactions with specific DNA sequences and other reg- ulatory proteins. To detect such interactions in Arabidopsis, we developed a high-throughput screening system with a Gateway-compatible Gal4-AD-TF library of 1589 Arabidopsis TFs, which can be easily screened by mating-based yeast-one-hybrid （YIH） and yeast-two-hybrid （Y2H） methods. The efficiency of the system was validated by examining two well-characterized TF-DNA and TF-protein interactions： the CHE-CCA1 promoter interaction by YIH and NPR1-TGAs interactions by Y2H. We used this system to identify eight TFs that interact with a Mediator subunit, Med25, a key reg- ulator in JA signaling. We identified five TFs that interacted with the GCC-box cis-element in the promoter of PDF1.2, a downstream gene of Med25. We found that three of these TFs, all from the AP2-EREBP family, interact directly both with Med25 and the GCC-box of PDF1.2, suggesting that Med25 regulates PDF1.2 expression through these three TFs. These results demonstrate that this high-throughput Y1H/Y2H screening system is an efficient tool for studying transcrip- tional regulation networks in Arabidopsis. This system will be available for other Arabidopsis researchers, and thus it provides a vital resource for the Arabidopsis community.展开更多
BACKGROUND: Midkine is a heparin-binding growth factor that promotes the proliferation, survival, migration and differentiation of various target cells. Midkine plays an important role in tumorigenesis and tumor progr...BACKGROUND: Midkine is a heparin-binding growth factor that promotes the proliferation, survival, migration and differentiation of various target cells. Midkine plays an important role in tumorigenesis and tumor progression, and is overexpressed in many human malignant tumors. Patients with high tumor midkine expression frequently have a worse prognosis than those with low expression. The present study was designed to investigate the interaction network of midkine in hepatic cancer cells, and to elucidate its role in hepatocellular carcinoma. METHODS: DNA encoding full-length midkine was cloned into pDBLeu vector to serve as bait in yeast two-hybrid screening to identify interacting proteins. Candidate proteins were examined on SC-Leu-Trp-His+3-AT (20 mmol/L) plates and assayed for X-gal activity, then sequenced and classified according to the GenBank. Finally, identified proteins were expressed by the in vitro expression system pCMVTnT, and protein interactions were confirmed by co-immunoprecipitation. RESULTS: Using the yeast two-hybrid system, we found 6 proteins that interacted with midkine: NK-kappa-B inhibitor alpha (I-κ-B-α), Dvl-binding protein naked cuticle 2, granulin, latent active TGF-β binding protein 3, latent active TGF-β binding protein 4, and phospholipid scramblase 1. In vitro co-immunoprecipitation demonstrated that all identified proteins directly interacted with midkine.CONCLUSION: The identification of midkine-interacting proteins in hepatic cancer cells indicates that midkine is a multifunctional factor that may participate in cell migration, differentiation, and proliferation, and is also associated with the multicellular response feedback during the development of hepatocellular carcinoma.展开更多
Research background: The Arabidopsis-resistance protein L5 (AT1G12290) can trigger cell death in Nicotiana benthamiana, which is a characteristic function of an NBS-LRR (Nucleotide-Binding Sites and Leucine-Rich Repea...Research background: The Arabidopsis-resistance protein L5 (AT1G12290) can trigger cell death in Nicotiana benthamiana, which is a characteristic function of an NBS-LRR (Nucleotide-Binding Sites and Leucine-Rich Repeat) protein activation. Purpose: To explore the function and molecular regulatory network of L5. Method: We employed yeast two-hybrid technology to search for interacting proteins of L5, combined with laser confocal microscopy to observe the subcellular localization of these candidate proteins, and analyzed the impact of these proteins on L5 function using an Agrobacterium mediated transient expression system. Results: Seven candidate interacting proteins were identified from the Arabidopsis cDNA library, including PPA1 (AT1G01050), RIN4 (AT3G25070), LSU1 (AT3G49580), BZIP24 (AT3G51960), BOI (AT4G19700), RING/U (AT4G22250) and PPA3 (AT2G46860). Functional analysis of these candidate interacting proteins showed that they participated in multiple pathways, including biological and abiotic stress, programmed cell death, protein degradation, material metabolism and transcriptional regulation. The results of laser confocal microscopy manifested that RIN4 was only localized on the plasma membrane (PM), and RING/U was mainly associated with the PM. PPA1, PPA3, LSU1, BZIP24, and BOI all emerged nuclear and cytoplasmic localization. The results of the transient assay proclaimed that both BOI and RING/U can inhibit cell death caused by L5. Conclusions: These results indicate that L5 immune receptors may participate in various pathways, and their protein levels and activities are strictly regulated at multiple levels, providing a basis for elucidating the mechanism of L5 immune receptors in Arabidopsis resistance.展开更多
Four human vascular endothelial growth factor receptor Flt-1 cDNA fragments containing extracellular domain loops 2, 1-2, 2-3 and 1-3 respectively were amplified from human placen-tal cDNA library by PCR and used for ...Four human vascular endothelial growth factor receptor Flt-1 cDNA fragments containing extracellular domain loops 2, 1-2, 2-3 and 1-3 respectively were amplified from human placen-tal cDNA library by PCR and used for screening ligand binding domains by yeast two-hybrid system. The result showed that, not only loop 1-3, but also the smaller fragment loop 2-3 could bind to hVEGF165. Recombinant expression plasmids pPIC9K/Flt-1(1-3) and pPIC9K/Flt-1 (2-3) were constructed and transformed to Pichia. pastoris host strain GS115, cultured in flasks, and expressed under the induction of 1 % methanol. The expressed product existed in supernatant in the form of soluble molecules and contained more than 60% of total protein after being induced for 4d. After being purified by CM-Sepharose FF and Sephacryl S-100 chromatography, its purity reached above 90%. Biological assay in vitro showed that the binding capacity of expressed soluble Flt-1 (2-3) to hVEGF165 and its inhibiting effect on the proliferation of human umbilical veins endothelial cells (HUVEC) stimulated with hVEGF165 were close to those of sFlt-1(1-3). Animal test showed that sFlt-1(2-3) could inhibit the formation of regenerate blood vessels stimulated with hVEGF165 significantly.展开更多
Two DNA fragments encoding PDZ domain （21-110 residues） and BAR domain （ 150-360 residues） from PICK1 （1-416 residues） were amplified by PCR and then introduced into vectors, pET-32M and pMAL-e2X respectively to...Two DNA fragments encoding PDZ domain （21-110 residues） and BAR domain （ 150-360 residues） from PICK1 （1-416 residues） were amplified by PCR and then introduced into vectors, pET-32M and pMAL-e2X respectively to generate recombinant plasmids, pE-pdz and pM-bar. Having been separately transferred into the hosts E. coli BL21 and E. coli JM109, these two strains can express fusion proteins： His-tagged PDZ（PDZ domain） and maltose binding protein-BAR（ MBP-BAR domain） respectively, as confirmed by both SDS-PAGE and Wostem blotting. The interaction between these two domains is dose-dependence, as identified by a pull-down test. Moreover, it has been shown from the ELISA analysis that the actual amount of PDZ bound to MBP-BAR-amylose beads reaches （ 16 ± 0. 5）%, as calculated by the molar ratio of PDZ to MBP-BAR. In addition, the interaction between BAR（bait） and PDZ（prey） in vivo was also examined with a yeast two-hybrid system.展开更多
To further research the regulatory network of pyruvate dehydrogenase kinase （designated as TaPDK） in physiological male-sterility （PHYMS） of wheat induced by chemical hybridizing agent （CHA） SQ-1, an anther cDNA...To further research the regulatory network of pyruvate dehydrogenase kinase （designated as TaPDK） in physiological male-sterility （PHYMS） of wheat induced by chemical hybridizing agent （CHA） SQ-1, an anther cDNA library was constructed, and the proteins interacting with TaPDK were screened via yeast two-hybrid technique. Subsequently, a few candidate proteins in nucleotide expression levels were detected by real-time quantitative PCR. Yeast-two hybrid screening was performed by mating yeast strain Y2HGold containing BD-TaPDK bait plasmid with yeast strain Y187 including anther cDNA library plasmid. Diploid yeast cells were plated on synthetic dropout nutrient medium （SD/-Ade/-His/-Leu/-Trp） （QDO）, and further were incubated on QDO medium containing AbA and X-α-Gal. The interactions between TaPDK and the proteins obtained from positive colonies were further confirmed by co-transformation validation. After plasmids DNA were extracted from blue colonies and sequenced, the sequences results were analyzed by bioinformatic methods. Finally, 24 colonies were obtained, including eight genes, namely non-specific lipid-transfer protein precursor （TanLTP）, polyubiquitin （TaPUbi）, glyceraldehyde-3-phosphate dehydrogenase, proliferating cell nuclear antigen （TaPCNA）, CBS domain containing protein （TaCBS）, actin, guanine nucleotide-binding protein beta subunit, chalcone synthase, and three new genes with unknown function. The results of quantitative RT-PCR showed that the expression levels of TanLTP, TaPUbi, and TaPCNA were obviously up-regulated in PHYMS anther, and TaCBS expression was only increased at the tricellular stage in PHYMS anther compared with in fertile lines. Whereas, the expression of TaPDK was obviously down-regulated in PHYMS lines. Collectively, these datas indicated that the majority of candidate proteins might be related to pollen abortion in PHYMS lines, which further suggested that TaPDK plays multiple roles in pollen development, besides participating in regulating p展开更多
Gram-negative bacteria have become the main pathogens and cause serious clinical problems with increased morbidity and mortality. However, the slow discovery of new antimicrobial agents is unable to meet the need for ...Gram-negative bacteria have become the main pathogens and cause serious clinical problems with increased morbidity and mortality. However, the slow discovery of new antimicrobial agents is unable to meet the need for the treatment of bacterial infections caused by drug-resistant strains. The interaction of L12 and L10 is essential for ribosomal function and protein synthesis. In this study, a yeast two-hybrid system was established to successfully detect the interaction between L12 and L10 proteins from gram-negative bacteria Escherichia coli, which allows us to screen compounds that specifically disrupt this interaction. With this system, we identified two compounds IMB-84 and IMB-87 that block L12-L10 interaction and show bactericidal activity against E. coli. We used glutathione-S-transferase(GST) pull-down and surface plasmon resonance(SPR) assays to demonstrate that these compounds disrupt L12-L10 interaction in vitro and the target of compounds was further confirmed by the overexpression of target proteins. Moreover, protein synthesis and elongation factor G-dependent GTPase activities are inhibited by two compounds. Therefore, we have identified two antibacterial agents that disrupt L12-L10 interaction by using yeast two-hybrid system.展开更多
The yeast two\|hybrid system is a molecular genetic approach for protein interaction and it is widely used to screen for proteins that interact with a protein of interest in recent years.This process includes,construc...The yeast two\|hybrid system is a molecular genetic approach for protein interaction and it is widely used to screen for proteins that interact with a protein of interest in recent years.This process includes,construction and testing of the bait plasmid,screening a plasmid library for interacting fusion protein,elimination of false positives and delection analysis of true positives.This procedure is designed to allow investigators to identify proteins and their encoding cDNAs that have a biologically significant interaction with a protein of interest.More and more studies have demonstrated that the two\|hybrid system is a powerful and sensitive technique for the identification of genes that code for proteins that interact in a biologically significant fashion with a protein of interest in higher plants.This method has been used to identify new interaction protein in many laboratories.The recently reported yeast tri\|brid system,should allow the investigation of more complex protein\|protein interactions.The aim of this review is to outline the recent progress made in protein interactions by using yeast two\|hybrid system.展开更多
To investigate the interaction of hTCF4, the yeast two-hybrid system has been used for testing the interaction of mutants of hTCF4 with themselves. Mutants of hTCF4 (hTCF4 Ⅰ ) and hTCF4 Ⅱ) have been obtained by poly...To investigate the interaction of hTCF4, the yeast two-hybrid system has been used for testing the interaction of mutants of hTCF4 with themselves. Mutants of hTCF4 (hTCF4 Ⅰ ) and hTCF4 Ⅱ) have been obtained by polymerase chain reaction (PCR). Bait (hTCF4 Ⅰ -pDBLeu and hTCF4Ⅱ-pDBLeu) and prey (hTCF4 Ⅰ -pPC86 and hTCF4Ⅱ-pPC86) have been constructed by DNA recombination for yeast two-hybrid. Interaction of hTCF4Ⅱ with itself is found in the reverse yeast two-hybrid system (GIBCOBRL Co.). However, no interactions are found in hTCF4Ⅱ with hTCF4 Ⅰ and in hTCF4 Ⅰ with hTCF4 Ⅰ . These results suggest that hTCF4 could interact with itself to form homodimer or homocopolymer and perform the transcriptional activating function through LZ or HLH motifs in nucleus of renal cell carcinoma.展开更多
Environmental chemicals in drinking water can impact human health through nuclear receptors. Additionally, estrogen-related receptors （ERRs） are vulnerable to endocrine-disrupting effects. To date, however, ERR disr...Environmental chemicals in drinking water can impact human health through nuclear receptors. Additionally, estrogen-related receptors （ERRs） are vulnerable to endocrine-disrupting effects. To date, however, ERR disruption of drinking water potency has not been reported. We used ERRy two-hybrid yeast assay to screen ERRy disrupting activities in a drinking water treatment plant （DWTP） located in north China and in source water from a reservoir, focusing on agonistic, antagonistic, and inverse agonistie activity to 4-hydroxytamoxifen （4-OHT）. Water treatment processes in the DWTP consisted of pre-chlorination, coagulation, coal and sand filtration, activated carbon filtration, and secondary chlorination processes. Samples were extracted by solid phase extraction. Results showed that ERRγ antagonistic activities were found in all sample extracts, but agonistic and inverse agonistic activity to 4-OHT was not found. When calibrated with the toxic equivalent of 4-OHT, antagonistic effluent effects ranged from 3.4 to 33.1 μg/L. In the treatment processes, secondary chlorination was effective in removing ERRy antagonists, but the coagulation process led to significantly increased ERRy antagonistic activity. The drinking water treatment processes removed 73.5 % of ERRy antagonists. To our knowledge, the occurrence of ERRy disruption activities on source and drinking water in vitro had not been reported previously. It is vital, therefore, to increase our understanding of ERRγ disrupting activities in drinking water.展开更多
Amyloid precursor protein （APP） plays a critical role in the formation of Alzheimer＇s disease （AD）. The intracellular domain APP （AID） was suggested to cause neurotoxicity in the nucleus. To investigate the fun...Amyloid precursor protein （APP） plays a critical role in the formation of Alzheimer＇s disease （AD）. The intracellular domain APP （AID） was suggested to cause neurotoxicity in the nucleus. To investigate the functions AID, yeast two-hybrid screening was performed to identify the proteins which interact with AID. The human brain cDNA library was screened using pGBKT7-AID as a bait, and several positive clones were identified. One of them encodes a part of the human stathmin-like 2 protein （STMN2）. The interaction between STMN2 and APP implies that STMN2 may have an important function in APP-mediated AD formation.展开更多
The yeast two-hybrid (Y2H) mating assay is a powerful method for detecting protein-protein interactions. Firstly, the gene of interest is cloned into specific Y2H vectors. Although multiple innovations in cloning meth...The yeast two-hybrid (Y2H) mating assay is a powerful method for detecting protein-protein interactions. Firstly, the gene of interest is cloned into specific Y2H vectors. Although multiple innovations in cloning methods were made in the past two decades, the conventional cloning method of restriction-enzyme (RE) digestion followed by ligation is still widely used. Unfortunately, many researchers, especially new-comers, often encounter difficulties in cloning a gene into a desired vector. Secondly, interaction between two proteins is commonly detected by growth of the diploids in specific media. This step takes about two weeks. Here, we describe improved cloning and detection procedures for the Y2H assay that accelerate the research progress. The changes in procedures involve running an agarose gel after the doubly digested vector and insert are ligated in the cloning step to determine the efficiency of RE digestion and ligation, and performing an additional replica-plating on plates for earlier assessment of interaction in the detection step. We show an example of Y2H interaction between Trs23 and Trs120 (respective subunits of TRAPP I and TRAPP II), as a proof of concept. By following the improved methods described here, the chances of successful cloning increased and the time for the whole Y2H experimental process is significantly shorter.展开更多
Integrin α11 (ITGA11) is one of the collagen-binding integrin α chains;however, its biological significance remains unknown. To determine the functions of ITGA11, we performed a yeast two-hybrid screen using the cyt...Integrin α11 (ITGA11) is one of the collagen-binding integrin α chains;however, its biological significance remains unknown. To determine the functions of ITGA11, we performed a yeast two-hybrid screen using the cytoplasmic domain of ITGA11 as bait and transformed an EGY48 yeast strain with the bait-containing plasmid using the plasmid from a human lung fibroblast cDNA library. This screen identified calcium- and integrin-binding protein 1 (CIB1) as prey. Recombinant ITGA11 and CIB1 were expressed in mammalian cells and used in coimmunoprecipitation experiments, which showed that full-length ITGA11 and CIB1 are also associated in vivo. Over-expression of CIB1 in the human lung myofibroblast MRC-5 cells decreased the expression of α-smooth muscle actin and fibronectin. Using a mouse model of pulmonary fibrosis (bleomycin-treatment), we detected elevated expression of CIB1 in lung tissues compared with controls. These data suggest that CIB1 may regulate pulmonary fibrosis in concert with IT-GA11.展开更多
Background Murine cytomegalovirus （MCMV） early protein Ml12-113 is involved in viral DNA replication and believed to play a crucial role in the viral pathogenesis. To investigate the biological function of Ml12-113 ...Background Murine cytomegalovirus （MCMV） early protein Ml12-113 is involved in viral DNA replication and believed to play a crucial role in the viral pathogenesis. To investigate the biological function of Ml12-113 protein in the pathogenesis of the brain disorders caused by cytomegalovirus （CMV）, a screening for proteins interacting with Ml12-113 was performed by a yeast two-hybrid system. Methods Bait plasmid pGBKT7-M112-113 was constructed and transformed into AH109 yeast. After confirmation of the expression of MCMV Ml12-113 in yeast, the bait yeast was mated with a prey yeast containing mouse brain cDNA library plasmid to screen the proteins interacting with M 112-113. Interactions between Ml12-113 and the obtained proteins were verified by yeast two-hybrid assay and chemiluminescent co-immunoprecipitaion. Results Two proteins interacting with M112-113 were identified, including metastasis-associated 1 （MTA1） and zinc finger, CCHC domain containing 18 （ZCCHC18）. Ml12-113 protein could interact with MTAt or ZCCHC18 in yeast and mammalian cells. Conclusion The interactions of Ml12-113 with MTA1 or ZCCHC18 may be related to the pathogenesis of MCMV-associated disease in central nervous system.展开更多
Rice black-streaked dwarf virus （RBSDV） is a recognized member of the genus Fijivirus, family Reoviridae. Its genome has ten double-stranded RNA （dsRNA） segments （$1-$10）, in which the fifth genome segment （$5...Rice black-streaked dwarf virus （RBSDV） is a recognized member of the genus Fijivirus, family Reoviridae. Its genome has ten double-stranded RNA （dsRNA） segments （$1-$10）, in which the fifth genome segment （$5） contains two open reading frames （ORFs） with a partially overlapping region. The second ORF of RBSDV S5 encodes a viral nonstructural protein named p5b with unknown function. To reveal the function of p5b, its gene was ligated into the bait plasmid pGBKT7 and an expression library containing rice cDNAs was constructed using plasmid pGADT7 for yeast two-hybrid assay. The bait protein p5b was detected in yeast by western blot, and the result of an auto-activation test showed that p5b could not autonomously activate the expression of reporter genes in yeast. Then the bait protein p5b was used for screening the cDNA expression libraries of rice. Gene fragments of some pivotal enzymes involved in photosynthesis, respiration and other important metabolic processes, were identified to interact with p5b in yeast, suggesting that these interactions may play roles in symptom development in infected plants.展开更多
[Objective] The paper was to obtain host proteins interacting with porcine epidemic diarrhea virus （PEDV） N protein. [Method] The re-combinant vector pGBKT7-N of PEDV N gene was constructed and used as the bait plas...[Objective] The paper was to obtain host proteins interacting with porcine epidemic diarrhea virus （PEDV） N protein. [Method] The re-combinant vector pGBKT7-N of PEDV N gene was constructed and used as the bait plasmid to screen the proteins interacting with N protein ofPEDV from the cDNA library of porcine alveolar macrophage （PAM） by yeast two-hybrid method. [Result] There was no toxicity and self activationof bait protein in yeast hybridization system, and six proteins （FTH1, LGALS3, CORO1C, SNRPG, KRTAP5-3, ZNF598） interacting with N proteinwere indentified. It was confirmed that LGALS3 and SNRPG had specific interaction with N protein by return experiment and co-immunoprecipitation（CoIP） test. [Conclusion] The study lays a foundation for further studying the function of PEDV N protein and the pathogenic mechanism of PEDV.展开更多
MAP kinase-interacting kinase-2 (Mnk2) is one of the downstream kinasesactivated by MAP kinases. It phosphorylates the eukaryotic initiation factor 4E (elF4E), althoughthe role of elF4E phosphorylation and the role of...MAP kinase-interacting kinase-2 (Mnk2) is one of the downstream kinasesactivated by MAP kinases. It phosphorylates the eukaryotic initiation factor 4E (elF4E), althoughthe role of elF4E phosphorylation and the role of Mnk2 in the process of proteintranslation are notwell understood. Except for elF4E, other physiological substrates of Mnk2 are still unidentified. Tolook for these unidentified substrates and to reveal the physiological function of Mnk2, weperformed a yeast two-hybrid screening with Mnk2 as the bait. The results demonstrated Mnk2 couldinteract with VHL (von Hippel-Lindau tumor suppressor), Rbx1 (ring-box1) and Cul2 (Cullin2) proteinsin yeast cells. Furthermore, we validated the interaction between Mnk2 and VHL proteins inmammalian cells by co-immunoprecipitation analysis. Because the three proteins VHL, Rbx1 and Cul2are all components of the CBC^(VHL) ubiquitin ligase E3 complex, it has been shown that Mnk2 caninteract with CBC^(VHL) complex, and is probably one of the newsubstrates of the CBC^(VHL) complex.Furthermore, during the interaction of Mnk2 with von Hippel-Lindau (VHL) tumor suppressor- bindingprotein 1 (VBP1), it appears that Mnk2 also joins to modulate cell shape as VBP1 plays an importantrole in the process of the maturation of the cytoskeleton and in the process of morphogenesis.展开更多
Abstract The broad-spectrum rice blast resistance gene Pik2-H4 was cloned from the highly resistant line H4. The full-length sequence of Pik2-H4 was 3 066 bp, which was different from the corresponding allele sequence...Abstract The broad-spectrum rice blast resistance gene Pik2-H4 was cloned from the highly resistant line H4. The full-length sequence of Pik2-H4 was 3 066 bp, which was different from the corresponding allele sequence of Nipponbare. Pik2-H4 belonged to NBS-LRR genes and coded a protein containing NB-ARC domain and leueine-rieh repeats. To find the interaction proteins with Pik2-H4 from the rice, the yeast two-hybrid system was used and three important proteins （ LOC- Os08939300, LOCOs03g25960 and LOC-Os09929130）were identified. The results could provide some new information for the mechanism of rice blast resistance mediated by Pik2-H4.展开更多
The POU domain transcription factor Oct4 is a master regulator in maintaining self-renewal and pluripotency of embryonic stem （ES） cells. To further explore the functional network of Oct4, the yeast two-hybrid syste...The POU domain transcription factor Oct4 is a master regulator in maintaining self-renewal and pluripotency of embryonic stem （ES） cells. To further explore the functional network of Oct4, the yeast two-hybrid system was used to search for Oct4 interacting proteins. PH domain （containing POU domain and homeodomain） of human OCT4 was used as a bait. From the human testis cDNA library, we identified a strong interaction between OCT4 and karyopberin-alpha 2 （KPNA-2）. KPNA2 is involved in active nuclear import of proteins. This finding was confirmed by glutathione S-transferase pull-down and co-immunoprecipitation assays. The interaction between OCT4 and KPNA-2 was further mapped to multiple regions of the two proteins. In addition, we studied nuclear localization signal （NLS） of mouse Oct4 and demonstrated that it is essential for Oct4 nuclear localization. Thus, our data suggest that Oct4 nuclear localization may be mediated by its interaction with KPNA-2.展开更多
文摘The activities of transcription factors （TFs） require interactions with specific DNA sequences and other reg- ulatory proteins. To detect such interactions in Arabidopsis, we developed a high-throughput screening system with a Gateway-compatible Gal4-AD-TF library of 1589 Arabidopsis TFs, which can be easily screened by mating-based yeast-one-hybrid （YIH） and yeast-two-hybrid （Y2H） methods. The efficiency of the system was validated by examining two well-characterized TF-DNA and TF-protein interactions： the CHE-CCA1 promoter interaction by YIH and NPR1-TGAs interactions by Y2H. We used this system to identify eight TFs that interact with a Mediator subunit, Med25, a key reg- ulator in JA signaling. We identified five TFs that interacted with the GCC-box cis-element in the promoter of PDF1.2, a downstream gene of Med25. We found that three of these TFs, all from the AP2-EREBP family, interact directly both with Med25 and the GCC-box of PDF1.2, suggesting that Med25 regulates PDF1.2 expression through these three TFs. These results demonstrate that this high-throughput Y1H/Y2H screening system is an efficient tool for studying transcrip- tional regulation networks in Arabidopsis. This system will be available for other Arabidopsis researchers, and thus it provides a vital resource for the Arabidopsis community.
基金supported by grants from the National Natural Science Foundation of China (30772534)the Natural Science Foundation of Huzhou (2010YS05)
文摘BACKGROUND: Midkine is a heparin-binding growth factor that promotes the proliferation, survival, migration and differentiation of various target cells. Midkine plays an important role in tumorigenesis and tumor progression, and is overexpressed in many human malignant tumors. Patients with high tumor midkine expression frequently have a worse prognosis than those with low expression. The present study was designed to investigate the interaction network of midkine in hepatic cancer cells, and to elucidate its role in hepatocellular carcinoma. METHODS: DNA encoding full-length midkine was cloned into pDBLeu vector to serve as bait in yeast two-hybrid screening to identify interacting proteins. Candidate proteins were examined on SC-Leu-Trp-His+3-AT (20 mmol/L) plates and assayed for X-gal activity, then sequenced and classified according to the GenBank. Finally, identified proteins were expressed by the in vitro expression system pCMVTnT, and protein interactions were confirmed by co-immunoprecipitation. RESULTS: Using the yeast two-hybrid system, we found 6 proteins that interacted with midkine: NK-kappa-B inhibitor alpha (I-κ-B-α), Dvl-binding protein naked cuticle 2, granulin, latent active TGF-β binding protein 3, latent active TGF-β binding protein 4, and phospholipid scramblase 1. In vitro co-immunoprecipitation demonstrated that all identified proteins directly interacted with midkine.CONCLUSION: The identification of midkine-interacting proteins in hepatic cancer cells indicates that midkine is a multifunctional factor that may participate in cell migration, differentiation, and proliferation, and is also associated with the multicellular response feedback during the development of hepatocellular carcinoma.
文摘Research background: The Arabidopsis-resistance protein L5 (AT1G12290) can trigger cell death in Nicotiana benthamiana, which is a characteristic function of an NBS-LRR (Nucleotide-Binding Sites and Leucine-Rich Repeat) protein activation. Purpose: To explore the function and molecular regulatory network of L5. Method: We employed yeast two-hybrid technology to search for interacting proteins of L5, combined with laser confocal microscopy to observe the subcellular localization of these candidate proteins, and analyzed the impact of these proteins on L5 function using an Agrobacterium mediated transient expression system. Results: Seven candidate interacting proteins were identified from the Arabidopsis cDNA library, including PPA1 (AT1G01050), RIN4 (AT3G25070), LSU1 (AT3G49580), BZIP24 (AT3G51960), BOI (AT4G19700), RING/U (AT4G22250) and PPA3 (AT2G46860). Functional analysis of these candidate interacting proteins showed that they participated in multiple pathways, including biological and abiotic stress, programmed cell death, protein degradation, material metabolism and transcriptional regulation. The results of laser confocal microscopy manifested that RIN4 was only localized on the plasma membrane (PM), and RING/U was mainly associated with the PM. PPA1, PPA3, LSU1, BZIP24, and BOI all emerged nuclear and cytoplasmic localization. The results of the transient assay proclaimed that both BOI and RING/U can inhibit cell death caused by L5. Conclusions: These results indicate that L5 immune receptors may participate in various pathways, and their protein levels and activities are strictly regulated at multiple levels, providing a basis for elucidating the mechanism of L5 immune receptors in Arabidopsis resistance.
基金National High Technology Programs of China (Grant No. 102-08-01-03) and Natural Science Fund Program of Guangdong Province (Grant No.001098).
文摘Four human vascular endothelial growth factor receptor Flt-1 cDNA fragments containing extracellular domain loops 2, 1-2, 2-3 and 1-3 respectively were amplified from human placen-tal cDNA library by PCR and used for screening ligand binding domains by yeast two-hybrid system. The result showed that, not only loop 1-3, but also the smaller fragment loop 2-3 could bind to hVEGF165. Recombinant expression plasmids pPIC9K/Flt-1(1-3) and pPIC9K/Flt-1 (2-3) were constructed and transformed to Pichia. pastoris host strain GS115, cultured in flasks, and expressed under the induction of 1 % methanol. The expressed product existed in supernatant in the form of soluble molecules and contained more than 60% of total protein after being induced for 4d. After being purified by CM-Sepharose FF and Sephacryl S-100 chromatography, its purity reached above 90%. Biological assay in vitro showed that the binding capacity of expressed soluble Flt-1 (2-3) to hVEGF165 and its inhibiting effect on the proliferation of human umbilical veins endothelial cells (HUVEC) stimulated with hVEGF165 were close to those of sFlt-1(1-3). Animal test showed that sFlt-1(2-3) could inhibit the formation of regenerate blood vessels stimulated with hVEGF165 significantly.
基金the National Natural Science Foundation of China(No 30400065)
文摘Two DNA fragments encoding PDZ domain （21-110 residues） and BAR domain （ 150-360 residues） from PICK1 （1-416 residues） were amplified by PCR and then introduced into vectors, pET-32M and pMAL-e2X respectively to generate recombinant plasmids, pE-pdz and pM-bar. Having been separately transferred into the hosts E. coli BL21 and E. coli JM109, these two strains can express fusion proteins： His-tagged PDZ（PDZ domain） and maltose binding protein-BAR（ MBP-BAR domain） respectively, as confirmed by both SDS-PAGE and Wostem blotting. The interaction between these two domains is dose-dependence, as identified by a pull-down test. Moreover, it has been shown from the ELISA analysis that the actual amount of PDZ bound to MBP-BAR-amylose beads reaches （ 16 ± 0. 5）%, as calculated by the molar ratio of PDZ to MBP-BAR. In addition, the interaction between BAR（bait） and PDZ（prey） in vivo was also examined with a yeast two-hybrid system.
基金supported by the National High-Tech R&D Program of China(2011AA10A106)the National Natural Science Foundation of China(31071477,31171611)the Key Scientific and Technological Innovation Special Projects of Shaanxi"13115",China(2010ZDKG-68,2011KTZB02-01-01)
文摘To further research the regulatory network of pyruvate dehydrogenase kinase （designated as TaPDK） in physiological male-sterility （PHYMS） of wheat induced by chemical hybridizing agent （CHA） SQ-1, an anther cDNA library was constructed, and the proteins interacting with TaPDK were screened via yeast two-hybrid technique. Subsequently, a few candidate proteins in nucleotide expression levels were detected by real-time quantitative PCR. Yeast-two hybrid screening was performed by mating yeast strain Y2HGold containing BD-TaPDK bait plasmid with yeast strain Y187 including anther cDNA library plasmid. Diploid yeast cells were plated on synthetic dropout nutrient medium （SD/-Ade/-His/-Leu/-Trp） （QDO）, and further were incubated on QDO medium containing AbA and X-α-Gal. The interactions between TaPDK and the proteins obtained from positive colonies were further confirmed by co-transformation validation. After plasmids DNA were extracted from blue colonies and sequenced, the sequences results were analyzed by bioinformatic methods. Finally, 24 colonies were obtained, including eight genes, namely non-specific lipid-transfer protein precursor （TanLTP）, polyubiquitin （TaPUbi）, glyceraldehyde-3-phosphate dehydrogenase, proliferating cell nuclear antigen （TaPCNA）, CBS domain containing protein （TaCBS）, actin, guanine nucleotide-binding protein beta subunit, chalcone synthase, and three new genes with unknown function. The results of quantitative RT-PCR showed that the expression levels of TanLTP, TaPUbi, and TaPCNA were obviously up-regulated in PHYMS anther, and TaCBS expression was only increased at the tricellular stage in PHYMS anther compared with in fertile lines. Whereas, the expression of TaPDK was obviously down-regulated in PHYMS lines. Collectively, these datas indicated that the majority of candidate proteins might be related to pollen abortion in PHYMS lines, which further suggested that TaPDK plays multiple roles in pollen development, besides participating in regulating p
基金supported by the National Natural Science Foundation of China (Grant nos.81370089,81529003,81621064 and 81361138020)the Foundation for Innovative Research Groups and the Funds for International Cooperation and Exchange between China–Sweden and CAMS Initiative for Innovative Medicine (2016-12M-3-014)
文摘Gram-negative bacteria have become the main pathogens and cause serious clinical problems with increased morbidity and mortality. However, the slow discovery of new antimicrobial agents is unable to meet the need for the treatment of bacterial infections caused by drug-resistant strains. The interaction of L12 and L10 is essential for ribosomal function and protein synthesis. In this study, a yeast two-hybrid system was established to successfully detect the interaction between L12 and L10 proteins from gram-negative bacteria Escherichia coli, which allows us to screen compounds that specifically disrupt this interaction. With this system, we identified two compounds IMB-84 and IMB-87 that block L12-L10 interaction and show bactericidal activity against E. coli. We used glutathione-S-transferase(GST) pull-down and surface plasmon resonance(SPR) assays to demonstrate that these compounds disrupt L12-L10 interaction in vitro and the target of compounds was further confirmed by the overexpression of target proteins. Moreover, protein synthesis and elongation factor G-dependent GTPase activities are inhibited by two compounds. Therefore, we have identified two antibacterial agents that disrupt L12-L10 interaction by using yeast two-hybrid system.
文摘The yeast two\|hybrid system is a molecular genetic approach for protein interaction and it is widely used to screen for proteins that interact with a protein of interest in recent years.This process includes,construction and testing of the bait plasmid,screening a plasmid library for interacting fusion protein,elimination of false positives and delection analysis of true positives.This procedure is designed to allow investigators to identify proteins and their encoding cDNAs that have a biologically significant interaction with a protein of interest.More and more studies have demonstrated that the two\|hybrid system is a powerful and sensitive technique for the identification of genes that code for proteins that interact in a biologically significant fashion with a protein of interest in higher plants.This method has been used to identify new interaction protein in many laboratories.The recently reported yeast tri\|brid system,should allow the investigation of more complex protein\|protein interactions.The aim of this review is to outline the recent progress made in protein interactions by using yeast two\|hybrid system.
文摘To investigate the interaction of hTCF4, the yeast two-hybrid system has been used for testing the interaction of mutants of hTCF4 with themselves. Mutants of hTCF4 (hTCF4 Ⅰ ) and hTCF4 Ⅱ) have been obtained by polymerase chain reaction (PCR). Bait (hTCF4 Ⅰ -pDBLeu and hTCF4Ⅱ-pDBLeu) and prey (hTCF4 Ⅰ -pPC86 and hTCF4Ⅱ-pPC86) have been constructed by DNA recombination for yeast two-hybrid. Interaction of hTCF4Ⅱ with itself is found in the reverse yeast two-hybrid system (GIBCOBRL Co.). However, no interactions are found in hTCF4Ⅱ with hTCF4 Ⅰ and in hTCF4 Ⅰ with hTCF4 Ⅰ . These results suggest that hTCF4 could interact with itself to form homodimer or homocopolymer and perform the transcriptional activating function through LZ or HLH motifs in nucleus of renal cell carcinoma.
基金supported by the National High Technology Research and Development Program (863) of China(No. 2007AA06Z414)the National Natural Science Foundation of China(No. 50778170)
文摘Environmental chemicals in drinking water can impact human health through nuclear receptors. Additionally, estrogen-related receptors （ERRs） are vulnerable to endocrine-disrupting effects. To date, however, ERR disruption of drinking water potency has not been reported. We used ERRy two-hybrid yeast assay to screen ERRy disrupting activities in a drinking water treatment plant （DWTP） located in north China and in source water from a reservoir, focusing on agonistic, antagonistic, and inverse agonistie activity to 4-hydroxytamoxifen （4-OHT）. Water treatment processes in the DWTP consisted of pre-chlorination, coagulation, coal and sand filtration, activated carbon filtration, and secondary chlorination processes. Samples were extracted by solid phase extraction. Results showed that ERRγ antagonistic activities were found in all sample extracts, but agonistic and inverse agonistic activity to 4-OHT was not found. When calibrated with the toxic equivalent of 4-OHT, antagonistic effluent effects ranged from 3.4 to 33.1 μg/L. In the treatment processes, secondary chlorination was effective in removing ERRy antagonists, but the coagulation process led to significantly increased ERRy antagonistic activity. The drinking water treatment processes removed 73.5 % of ERRy antagonists. To our knowledge, the occurrence of ERRy disruption activities on source and drinking water in vitro had not been reported previously. It is vital, therefore, to increase our understanding of ERRγ disrupting activities in drinking water.
基金Supported by the National Natural Science Foundation of China (Nos. 30125021 and 30270681), the Bugher Foundation (New York), and the SRFDP of the Ministry of Education of China
文摘Amyloid precursor protein （APP） plays a critical role in the formation of Alzheimer＇s disease （AD）. The intracellular domain APP （AID） was suggested to cause neurotoxicity in the nucleus. To investigate the functions AID, yeast two-hybrid screening was performed to identify the proteins which interact with AID. The human brain cDNA library was screened using pGBKT7-AID as a bait, and several positive clones were identified. One of them encodes a part of the human stathmin-like 2 protein （STMN2）. The interaction between STMN2 and APP implies that STMN2 may have an important function in APP-mediated AD formation.
文摘The yeast two-hybrid (Y2H) mating assay is a powerful method for detecting protein-protein interactions. Firstly, the gene of interest is cloned into specific Y2H vectors. Although multiple innovations in cloning methods were made in the past two decades, the conventional cloning method of restriction-enzyme (RE) digestion followed by ligation is still widely used. Unfortunately, many researchers, especially new-comers, often encounter difficulties in cloning a gene into a desired vector. Secondly, interaction between two proteins is commonly detected by growth of the diploids in specific media. This step takes about two weeks. Here, we describe improved cloning and detection procedures for the Y2H assay that accelerate the research progress. The changes in procedures involve running an agarose gel after the doubly digested vector and insert are ligated in the cloning step to determine the efficiency of RE digestion and ligation, and performing an additional replica-plating on plates for earlier assessment of interaction in the detection step. We show an example of Y2H interaction between Trs23 and Trs120 (respective subunits of TRAPP I and TRAPP II), as a proof of concept. By following the improved methods described here, the chances of successful cloning increased and the time for the whole Y2H experimental process is significantly shorter.
文摘Integrin α11 (ITGA11) is one of the collagen-binding integrin α chains;however, its biological significance remains unknown. To determine the functions of ITGA11, we performed a yeast two-hybrid screen using the cytoplasmic domain of ITGA11 as bait and transformed an EGY48 yeast strain with the bait-containing plasmid using the plasmid from a human lung fibroblast cDNA library. This screen identified calcium- and integrin-binding protein 1 (CIB1) as prey. Recombinant ITGA11 and CIB1 were expressed in mammalian cells and used in coimmunoprecipitation experiments, which showed that full-length ITGA11 and CIB1 are also associated in vivo. Over-expression of CIB1 in the human lung myofibroblast MRC-5 cells decreased the expression of α-smooth muscle actin and fibronectin. Using a mouse model of pulmonary fibrosis (bleomycin-treatment), we detected elevated expression of CIB1 in lung tissues compared with controls. These data suggest that CIB1 may regulate pulmonary fibrosis in concert with IT-GA11.
基金This study was supported by a grant from National Natural Science Foundation of China （No. 30671859）.
文摘Background Murine cytomegalovirus （MCMV） early protein Ml12-113 is involved in viral DNA replication and believed to play a crucial role in the viral pathogenesis. To investigate the biological function of Ml12-113 protein in the pathogenesis of the brain disorders caused by cytomegalovirus （CMV）, a screening for proteins interacting with Ml12-113 was performed by a yeast two-hybrid system. Methods Bait plasmid pGBKT7-M112-113 was constructed and transformed into AH109 yeast. After confirmation of the expression of MCMV Ml12-113 in yeast, the bait yeast was mated with a prey yeast containing mouse brain cDNA library plasmid to screen the proteins interacting with M 112-113. Interactions between Ml12-113 and the obtained proteins were verified by yeast two-hybrid assay and chemiluminescent co-immunoprecipitaion. Results Two proteins interacting with M112-113 were identified, including metastasis-associated 1 （MTA1） and zinc finger, CCHC domain containing 18 （ZCCHC18）. Ml12-113 protein could interact with MTAt or ZCCHC18 in yeast and mammalian cells. Conclusion The interactions of Ml12-113 with MTA1 or ZCCHC18 may be related to the pathogenesis of MCMV-associated disease in central nervous system.
基金funded by the National Science and Technology Support Program of China(Grant No.2012BAD19B03)the National High Technology Research and Development Program of China(Grant No.2007AA10Z414)+4 种基金the National Basic Research Program of China(Grant No.2010CB126203)the International Science and Technology Cooperation Project(Grant No.2007DFB30350)the Special Fund for Agro-scientific Research in the Public Interest of China(Grant No.201003031)the Zhejiang Provincial Science and Technology Project,China(Grant No.2010C12027)the Zhejiang Provincial Foundation for Natural Science,China(Grant Nos.Z305165and Y3090657)
文摘Rice black-streaked dwarf virus （RBSDV） is a recognized member of the genus Fijivirus, family Reoviridae. Its genome has ten double-stranded RNA （dsRNA） segments （$1-$10）, in which the fifth genome segment （$5） contains two open reading frames （ORFs） with a partially overlapping region. The second ORF of RBSDV S5 encodes a viral nonstructural protein named p5b with unknown function. To reveal the function of p5b, its gene was ligated into the bait plasmid pGBKT7 and an expression library containing rice cDNAs was constructed using plasmid pGADT7 for yeast two-hybrid assay. The bait protein p5b was detected in yeast by western blot, and the result of an auto-activation test showed that p5b could not autonomously activate the expression of reporter genes in yeast. Then the bait protein p5b was used for screening the cDNA expression libraries of rice. Gene fragments of some pivotal enzymes involved in photosynthesis, respiration and other important metabolic processes, were identified to interact with p5b in yeast, suggesting that these interactions may play roles in symptom development in infected plants.
基金Supported by National Natural Science Foundation of China(31201915,31502071)Key Project of Science and Technology Promoting Agriculture in Shanghai City[HNKGZ(2013)No.3-6,No.5-5]
文摘[Objective] The paper was to obtain host proteins interacting with porcine epidemic diarrhea virus （PEDV） N protein. [Method] The re-combinant vector pGBKT7-N of PEDV N gene was constructed and used as the bait plasmid to screen the proteins interacting with N protein ofPEDV from the cDNA library of porcine alveolar macrophage （PAM） by yeast two-hybrid method. [Result] There was no toxicity and self activationof bait protein in yeast hybridization system, and six proteins （FTH1, LGALS3, CORO1C, SNRPG, KRTAP5-3, ZNF598） interacting with N proteinwere indentified. It was confirmed that LGALS3 and SNRPG had specific interaction with N protein by return experiment and co-immunoprecipitation（CoIP） test. [Conclusion] The study lays a foundation for further studying the function of PEDV N protein and the pathogenic mechanism of PEDV.
文摘MAP kinase-interacting kinase-2 (Mnk2) is one of the downstream kinasesactivated by MAP kinases. It phosphorylates the eukaryotic initiation factor 4E (elF4E), althoughthe role of elF4E phosphorylation and the role of Mnk2 in the process of proteintranslation are notwell understood. Except for elF4E, other physiological substrates of Mnk2 are still unidentified. Tolook for these unidentified substrates and to reveal the physiological function of Mnk2, weperformed a yeast two-hybrid screening with Mnk2 as the bait. The results demonstrated Mnk2 couldinteract with VHL (von Hippel-Lindau tumor suppressor), Rbx1 (ring-box1) and Cul2 (Cullin2) proteinsin yeast cells. Furthermore, we validated the interaction between Mnk2 and VHL proteins inmammalian cells by co-immunoprecipitation analysis. Because the three proteins VHL, Rbx1 and Cul2are all components of the CBC^(VHL) ubiquitin ligase E3 complex, it has been shown that Mnk2 caninteract with CBC^(VHL) complex, and is probably one of the newsubstrates of the CBC^(VHL) complex.Furthermore, during the interaction of Mnk2 with von Hippel-Lindau (VHL) tumor suppressor- bindingprotein 1 (VBP1), it appears that Mnk2 also joins to modulate cell shape as VBP1 plays an importantrole in the process of the maturation of the cytoskeleton and in the process of morphogenesis.
基金Supported by Specialized Research Fund for the Doctoral Program of Higher Education"Resistance Mechanism of Rice Blast Resistance Gene Pik-m"(20124404120007)
文摘Abstract The broad-spectrum rice blast resistance gene Pik2-H4 was cloned from the highly resistant line H4. The full-length sequence of Pik2-H4 was 3 066 bp, which was different from the corresponding allele sequence of Nipponbare. Pik2-H4 belonged to NBS-LRR genes and coded a protein containing NB-ARC domain and leueine-rieh repeats. To find the interaction proteins with Pik2-H4 from the rice, the yeast two-hybrid system was used and three important proteins （ LOC- Os08939300, LOCOs03g25960 and LOC-Os09929130）were identified. The results could provide some new information for the mechanism of rice blast resistance mediated by Pik2-H4.
基金supported by the Shanghai Science & Technology Developmental Foundations (No.06dj14001)the National High Technology Research and Development Program of China (No. 2006AA02Z197, 2006CB943901, and 2007CB947904)
文摘The POU domain transcription factor Oct4 is a master regulator in maintaining self-renewal and pluripotency of embryonic stem （ES） cells. To further explore the functional network of Oct4, the yeast two-hybrid system was used to search for Oct4 interacting proteins. PH domain （containing POU domain and homeodomain） of human OCT4 was used as a bait. From the human testis cDNA library, we identified a strong interaction between OCT4 and karyopberin-alpha 2 （KPNA-2）. KPNA2 is involved in active nuclear import of proteins. This finding was confirmed by glutathione S-transferase pull-down and co-immunoprecipitation assays. The interaction between OCT4 and KPNA-2 was further mapped to multiple regions of the two proteins. In addition, we studied nuclear localization signal （NLS） of mouse Oct4 and demonstrated that it is essential for Oct4 nuclear localization. Thus, our data suggest that Oct4 nuclear localization may be mediated by its interaction with KPNA-2.
