microRNAs(miRNAs)have emerged as key components in the eukaryotic gene regulatory network.We and others have previously identified many miRNAs in a unicellular green alga,Chlamydomonas reinhardtii.To investigate wheth...microRNAs(miRNAs)have emerged as key components in the eukaryotic gene regulatory network.We and others have previously identified many miRNAs in a unicellular green alga,Chlamydomonas reinhardtii.To investigate whether miRNA-mediated gene regulation is a general mechanism in green algae and how miRNAs have been evolved in the green algal lineage,we examined small RNAs in Volvox carteri,a multicellular species in the same family with Chlamydomonas reinhardtii.We identified 174 miRNAs in Volvox,with many of them being highly enriched in gonidia or somatic cells.The targets of the miRNAs were predicted and many of them were subjected to miRNA-mediated cleavage in vivo,suggesting that miRNAs play regulatory roles in the biology of green algae.Our catalog of miRNAs and their targets provides a resource for further studies on the evolution,biological functions,and genomic properties of miRNAs in green algae.展开更多
In many eukaryotic organisms, Cdcl4 phosphatase regulates multiple biological events during anaphase and is essential for mitosis. It has been shown that Cdcl4 is required for sporulation in the potato blight pathogen...In many eukaryotic organisms, Cdcl4 phosphatase regulates multiple biological events during anaphase and is essential for mitosis. It has been shown that Cdcl4 is required for sporulation in the potato blight pathogen Phytophthora infestans; howev- er, the role that the Cdcl4 homolog （PsCdcl4） plays in the soil-borne soybean root rot pathogen P. sojae remains ambiguous. PsCdc14 is highly expressed in spornlation, zoospore, and cyst life stages, but not in vegetative mycelia and infection stages, suggesting that it contributes to asexual reproduction and thus the spread of the disease. Double-stranded RNA （dsRNA） medi- ates gene silencing, a post-transcriptional and highly conserved process in eukaryotes, involving specific gene silencing through degradation of target mRNA. We combined in vitro dsRNA synthesis and a polyethylene glycol-mediated transfor- marion system to construct a dsRNA-mediated transient gene silencing system; and then performed a functional analysis of PsCdcl4 in P. sojae. PsCdc14 mRNA was dramatically reduced in transformants after protoplasts were exposed in in vitro synthesized PsCdc14 dsRNA, resulting in low sporangial production and abnormal development in P. sojae silencing lines. Furthermore, dsRNA-mediated transient gene silencing could enable elucidation of P. sojae rapid gene function, facilitating our understanding of the development and pathogenicity mechanisms of this oomycete fungus.展开更多
AIM： To determine the functional significance of TC21 in esophageal squamous cell carcinoma （ESCC）. METHODS： TC21 siRNA transfection was carried out using Hyperfectamine to knock down TC21, and tran- scripts were ...AIM： To determine the functional significance of TC21 in esophageal squamous cell carcinoma （ESCC）. METHODS： TC21 siRNA transfection was carried out using Hyperfectamine to knock down TC21, and tran- scripts were analyzed by reverse transcription-poly- merase chain reaction and protein by Western blotting.We demonstrated the effect of TC21 downregulation of cell signaling in esophageal cancer cells by assess- ing the phosphorylation status of its downstream tar- gets, phosphoinositide 3-kinase （PI3K）, phosphatase and tensin homolog （PTEN）, protein kinase B （pAl〈t）, nuclear factor-KB （NF-~B） and cyclinD1 using specific antibodies. Cell survival analysis after cisplatin treat- ment was carried out by cell viability assay and cell cycle analysis using flow cytometry. RESULTS： TC21 knockdown in human ESCC cell line TEl3 cells, showed only a marginal increase （14.2%） in cell death compared with control cells. The expres- sions of the signaling proteins PI3K and pAkt, transcrip- tion factor NF-KB, and cell cycle protein cyclin D1 were markedly decreased in response to TC21 downregula- tion, whereas the level of pPTEN, an antagonist of PI3K, was increased. In addition, we evaluated the potential of TC21 as a putative target for sensitizing ESCC cells to the chemotherapeutic agent cisplatin. Increased cell death （38.4%） was observed in cells treated with cis- platin after TC21 knockdown compared with cells which were treated with cisplatin alone （20% cell death）. CONCLUSION： Results suggest that TC21 mediates its effects via the PI3K-Akt pathway, NF-KB and cyclin D1, and enhances chemoresistance in esophageal cancer cells.展开更多
Most eukaryotes employ a variety of mechanisms to defend the integrity of their genome by recognizing and silencing parasitic mobile nucleic acids.However,recent studies have shown that genomic DNA undergoes extensive...Most eukaryotes employ a variety of mechanisms to defend the integrity of their genome by recognizing and silencing parasitic mobile nucleic acids.However,recent studies have shown that genomic DNA undergoes extensive rearrangements,including DNA elimination,fragmentation,and unscrambling,during the sexual reproduction of ciliated protozoa.Non-coding RNAs have been identified to program and regulate genome rearrangement events.In Paramecium and Tetrahymena,scan RNAs(scnRNAs)are produced from micronuclei and transported to vegetative macronuclei,in which scnRNA elicits the elimination of cognate genomic DNA.In contrast,Piwi-interacting RNAs(piRNAs)in Oxytricha enable the retention of genomic DNA that exhibits sequence complementarity in macronuclei.An RNA interference(RNAi)-like mechanism has been found to direct these genomic rearrangements.Furthermore,in Oxytricha,maternal RNA templates can guide the unscrambling process of genomic DNA.The non-coding RNA-directed genome rearrangements may have profound evolutionary implications,for example,eliciting the multigenerational inheritance of acquired adaptive traits.展开更多
基金supported by the National Natural Science Foundation of China(31225015)National Basic Research Program of China(2012CB910900)to Qi YiJun
文摘microRNAs(miRNAs)have emerged as key components in the eukaryotic gene regulatory network.We and others have previously identified many miRNAs in a unicellular green alga,Chlamydomonas reinhardtii.To investigate whether miRNA-mediated gene regulation is a general mechanism in green algae and how miRNAs have been evolved in the green algal lineage,we examined small RNAs in Volvox carteri,a multicellular species in the same family with Chlamydomonas reinhardtii.We identified 174 miRNAs in Volvox,with many of them being highly enriched in gonidia or somatic cells.The targets of the miRNAs were predicted and many of them were subjected to miRNA-mediated cleavage in vivo,suggesting that miRNAs play regulatory roles in the biology of green algae.Our catalog of miRNAs and their targets provides a resource for further studies on the evolution,biological functions,and genomic properties of miRNAs in green algae.
基金supported by the Special Fund for Agro-Scientific Research in the Public Interest (Grant No. 3-20) from the Chinese governmentthe Priority Academic Program Development for Jiangsu Higher Education Institutions
文摘In many eukaryotic organisms, Cdcl4 phosphatase regulates multiple biological events during anaphase and is essential for mitosis. It has been shown that Cdcl4 is required for sporulation in the potato blight pathogen Phytophthora infestans; howev- er, the role that the Cdcl4 homolog （PsCdcl4） plays in the soil-borne soybean root rot pathogen P. sojae remains ambiguous. PsCdc14 is highly expressed in spornlation, zoospore, and cyst life stages, but not in vegetative mycelia and infection stages, suggesting that it contributes to asexual reproduction and thus the spread of the disease. Double-stranded RNA （dsRNA） medi- ates gene silencing, a post-transcriptional and highly conserved process in eukaryotes, involving specific gene silencing through degradation of target mRNA. We combined in vitro dsRNA synthesis and a polyethylene glycol-mediated transfor- marion system to construct a dsRNA-mediated transient gene silencing system; and then performed a functional analysis of PsCdcl4 in P. sojae. PsCdc14 mRNA was dramatically reduced in transformants after protoplasts were exposed in in vitro synthesized PsCdc14 dsRNA, resulting in low sporangial production and abnormal development in P. sojae silencing lines. Furthermore, dsRNA-mediated transient gene silencing could enable elucidation of P. sojae rapid gene function, facilitating our understanding of the development and pathogenicity mechanisms of this oomycete fungus.
基金Supported by Department of Science and Technology,Government of India
文摘AIM： To determine the functional significance of TC21 in esophageal squamous cell carcinoma （ESCC）. METHODS： TC21 siRNA transfection was carried out using Hyperfectamine to knock down TC21, and tran- scripts were analyzed by reverse transcription-poly- merase chain reaction and protein by Western blotting.We demonstrated the effect of TC21 downregulation of cell signaling in esophageal cancer cells by assess- ing the phosphorylation status of its downstream tar- gets, phosphoinositide 3-kinase （PI3K）, phosphatase and tensin homolog （PTEN）, protein kinase B （pAl〈t）, nuclear factor-KB （NF-~B） and cyclinD1 using specific antibodies. Cell survival analysis after cisplatin treat- ment was carried out by cell viability assay and cell cycle analysis using flow cytometry. RESULTS： TC21 knockdown in human ESCC cell line TEl3 cells, showed only a marginal increase （14.2%） in cell death compared with control cells. The expres- sions of the signaling proteins PI3K and pAkt, transcrip- tion factor NF-KB, and cell cycle protein cyclin D1 were markedly decreased in response to TC21 downregula- tion, whereas the level of pPTEN, an antagonist of PI3K, was increased. In addition, we evaluated the potential of TC21 as a putative target for sensitizing ESCC cells to the chemotherapeutic agent cisplatin. Increased cell death （38.4%） was observed in cells treated with cis- platin after TC21 knockdown compared with cells which were treated with cisplatin alone （20% cell death）. CONCLUSION： Results suggest that TC21 mediates its effects via the PI3K-Akt pathway, NF-KB and cyclin D1, and enhances chemoresistance in esophageal cancer cells.
基金supported by grants from the National Basic Research Program of China(2011CBA01103)the National Natural Science Foundation of China(31171254)the Fundamental Research Funds for Central Universities(WK2060190018)
文摘Most eukaryotes employ a variety of mechanisms to defend the integrity of their genome by recognizing and silencing parasitic mobile nucleic acids.However,recent studies have shown that genomic DNA undergoes extensive rearrangements,including DNA elimination,fragmentation,and unscrambling,during the sexual reproduction of ciliated protozoa.Non-coding RNAs have been identified to program and regulate genome rearrangement events.In Paramecium and Tetrahymena,scan RNAs(scnRNAs)are produced from micronuclei and transported to vegetative macronuclei,in which scnRNA elicits the elimination of cognate genomic DNA.In contrast,Piwi-interacting RNAs(piRNAs)in Oxytricha enable the retention of genomic DNA that exhibits sequence complementarity in macronuclei.An RNA interference(RNAi)-like mechanism has been found to direct these genomic rearrangements.Furthermore,in Oxytricha,maternal RNA templates can guide the unscrambling process of genomic DNA.The non-coding RNA-directed genome rearrangements may have profound evolutionary implications,for example,eliciting the multigenerational inheritance of acquired adaptive traits.
