Terrestrial plants have two to four times more ATP-binding cassette （ABC） transporter genes than other organisms, including their ancestral microalgae. Recent studies found that plants harboring mutations in these t...Terrestrial plants have two to four times more ATP-binding cassette （ABC） transporter genes than other organisms, including their ancestral microalgae. Recent studies found that plants harboring mutations in these transporters exhibit dramatic phenotypes, many of which are related to developmental processes and functions necessary for life on dry land. These results suggest that ABC transporters multiplied during evolution and assumed novel functions that allowed plants to adapt to terrestrial environmental conditions. Examining the literature on plant ABC transporters from this viewpoint led us to propose that diverse ABC transporters enabled many unique and essential aspects of a terrestrial plant＇s lifestyle, by transporting various compounds across specific membranes of the plant.展开更多
Evolution of resistance to Cry proteins in multiple pest insects has been threatening the sustainable use of Bacillus thuringiensis(Bt)-transgenic crops.Better understanding about the mechanism of resistance to Cry pr...Evolution of resistance to Cry proteins in multiple pest insects has been threatening the sustainable use of Bacillus thuringiensis(Bt)-transgenic crops.Better understanding about the mechanism of resistance to Cry proteins in insects is needed.Our preliminary study reported that the transcription of HaABCC3 was significantly decreased in a near-isogenic line(LFC2)of a Cry1Ac-resistant strain(LF60)of the global pest Helicoverpa armigera.However,the causality between HaABCC3 downregulation and resistance to Cry1Ac remains to be verified,and the regulatory mechanism underlying the HaABCC3 downregulation is still unclear.In this study,our data showed that both HaABCC3 and HaABCC3 downregulation were genetically linked to resistance to Cry1Ac in LF60.However,no InDels were observed in the coding sequence of HaABCC3 from LF60.Furthermore,F_(1) offspring from the cross of LF60 and a HaABCC2/3-knockout mutant exhibited moderate resistance to Cry1Ac toxin;this indicated that the high resistance to CrylAc toxin in LF60 may have resulted from multiple genetic factors,including HaABCC2 missplicing and HaABCC3 downregulation.Results from luciferase reporter assays showed that promoter activity of HaABCC3 in LF60 was significantly lower than that in the susceptible strain,which indicated that HaABCC3 downregulation was likely mediated by promoter variation.Consistently,multiple variations of the GATA-or FoxA-binding sites in the promoter region of HaABCC3 were identified.Collectively,all results in this study suggested that the downregulation of HaABCC3 observed in the H.armigera LF60 strain,which is resistant to CrylAc,may be mediated by a cis-regulatory mechanism.展开更多
Breast cancer is the most common malignancy in women worldwide.Triplenegative breast cancer(TNBC),refers breast cancer negative for estrogen receptor,progesterone receptor and human epidermal growth factor receptor 2,...Breast cancer is the most common malignancy in women worldwide.Triplenegative breast cancer(TNBC),refers breast cancer negative for estrogen receptor,progesterone receptor and human epidermal growth factor receptor 2,characterized by high drug resistance,high metastasis and high recurrence,treatment of which is a difficult problem in the clinical treatment of breast cancer.In order to better treat TNBC clinically,it is a very urgent task to explore the mechanism of TNBC resistance in basic breast cancer research.Pregnane X receptor(PXR)is a nuclear receptor whose main biological function is to participate in the metabolism,transport and clearance of allobiological agents in PXR.PXR plays an important role in drug metabolism and clearance,and PXR is highly expressed in tumor tissues of TNBC patients,which is related to the prognosis of breast cancer patients.This reviews synthesized the important role of PXR in the process of high drug resistance to TNBC chemotherapeutic drugs and related research progress.展开更多
Zinc(Zn) is an essential trace mineral that is required for plant growth and development. A number of protein transporters, which are involved in Zn uptake, translocation and distribution, are finely regulated to main...Zinc(Zn) is an essential trace mineral that is required for plant growth and development. A number of protein transporters, which are involved in Zn uptake, translocation and distribution, are finely regulated to maintain Zn homeostasis in plant. In this study, we functionally characterized an ATP-binding cassette(ABC) transporter gene, OsPDR7, which is involved in Zn homeostasis. Os PDR7 encodes a plasma membrane-localized protein that is expressed mainly in the exodermis and xylem in the rice root.ospdr7 mutants resulted in higher Zn accumulation compared with the wild type. Heterogeneous expression of OsPDR7 in a yeast mutant rescued the Zn-deficiency phenotype, implying transport activity of OsPDR7 to Zn in yeast. However, no ZIP genes except for OsZIP9 showed change in expression profile in the ospdr7 mutants, which suggested that OsPDR7 maintains cellular Zn homeostasis through regulating Os ZIP9 expression. RNA-Seq analysis further revealed a set of differentially expressed genes between the wild type and ospdr7 mutants that allowed us to propose a possible OsPDR7-associated signaling network involving transporters, hormone responsive genes, and transcription factors. Our results revealed a novel transporter involved in the regulation of Zn homeostasis and will pave the way toward a better understanding of the fine-tuning of gene expression in the network of transporter genes.展开更多
The reuse of dichlorodiphenyltrichloroethane(DDT) as an indoor residual spray was permitted by the World Health Organization in 2007, and approximately 14 countries still use DDT to control disease vectors. The extens...The reuse of dichlorodiphenyltrichloroethane(DDT) as an indoor residual spray was permitted by the World Health Organization in 2007, and approximately 14 countries still use DDT to control disease vectors. The extensive exposure of insects to DDT has resulted in the emergence of DDT resistance, especially in mosquitoes, and the mechanism for this resistance in mosquitoes has been widely reported. Spraying can also introduce DDT directly into surface water, and DDT can subsequently accumulate in microorganisms, but the mechanism for the resistance to DDT degradation in microorganisms is unclear. Using whole-genome microarray analysis, we detected an abcb15 gene that was up-regulated in a specific manner by DDT treatment in T. thermophile. The deduced ABCB15 peptide sequence had two transmembrane domains(TMDs) and two nucleotide-binding domains(NBDs) to form the structure TMD-NBD-TMD-NBD, and each NBD contained three conserved motifs: Walker-A, C-loop, and Walker-B, which indicated the T. thermophila abcb15 was a typical ABC transporter gene. The expression of ABCB15 fused with a C-terminal green fluorescent protein was found to be on the periphery of the cell, suggesting that ABCB15 was a membrane pump protein. In addition, cells with abcb15 partially knocked down(abcb15-KD) grew slower than wild-type cells in the presence of 256 mg L-1 DDT, indicating the tolerance of abcb15-KD strain to DDT exposure was decreased. Thus, we suggest that in Tetrahymena, the membrane pump protein encoded by ABCT gene abcb15 can enhance the tolerance to DDT and protect cells from this exogenous toxin by efficiently pumping it to the extracellular space.展开更多
文摘Terrestrial plants have two to four times more ATP-binding cassette （ABC） transporter genes than other organisms, including their ancestral microalgae. Recent studies found that plants harboring mutations in these transporters exhibit dramatic phenotypes, many of which are related to developmental processes and functions necessary for life on dry land. These results suggest that ABC transporters multiplied during evolution and assumed novel functions that allowed plants to adapt to terrestrial environmental conditions. Examining the literature on plant ABC transporters from this viewpoint led us to propose that diverse ABC transporters enabled many unique and essential aspects of a terrestrial plant＇s lifestyle, by transporting various compounds across specific membranes of the plant.
基金supported by the Biotechnology and Biological Sciences Research Council and the Cystic Fibrosis Trust.H Li was supported by EuroCareCF(LSHM-CT-2005-018932)while J-H Chen and Z Xu were supported by scholarships from the University of Bristol and ORS awards from Universities UK.
基金supported by Shenzhen Natural Science Foundation(grant numberJCYJ20200109150629266)Shenzhen Science and Technology Program(grant number KQTD20180411143628272).
文摘Evolution of resistance to Cry proteins in multiple pest insects has been threatening the sustainable use of Bacillus thuringiensis(Bt)-transgenic crops.Better understanding about the mechanism of resistance to Cry proteins in insects is needed.Our preliminary study reported that the transcription of HaABCC3 was significantly decreased in a near-isogenic line(LFC2)of a Cry1Ac-resistant strain(LF60)of the global pest Helicoverpa armigera.However,the causality between HaABCC3 downregulation and resistance to Cry1Ac remains to be verified,and the regulatory mechanism underlying the HaABCC3 downregulation is still unclear.In this study,our data showed that both HaABCC3 and HaABCC3 downregulation were genetically linked to resistance to Cry1Ac in LF60.However,no InDels were observed in the coding sequence of HaABCC3 from LF60.Furthermore,F_(1) offspring from the cross of LF60 and a HaABCC2/3-knockout mutant exhibited moderate resistance to Cry1Ac toxin;this indicated that the high resistance to CrylAc toxin in LF60 may have resulted from multiple genetic factors,including HaABCC2 missplicing and HaABCC3 downregulation.Results from luciferase reporter assays showed that promoter activity of HaABCC3 in LF60 was significantly lower than that in the susceptible strain,which indicated that HaABCC3 downregulation was likely mediated by promoter variation.Consistently,multiple variations of the GATA-or FoxA-binding sites in the promoter region of HaABCC3 were identified.Collectively,all results in this study suggested that the downregulation of HaABCC3 observed in the H.armigera LF60 strain,which is resistant to CrylAc,may be mediated by a cis-regulatory mechanism.
基金Supported by Science project of Hunan Provincial Health Commission,No.B202304089304.
文摘Breast cancer is the most common malignancy in women worldwide.Triplenegative breast cancer(TNBC),refers breast cancer negative for estrogen receptor,progesterone receptor and human epidermal growth factor receptor 2,characterized by high drug resistance,high metastasis and high recurrence,treatment of which is a difficult problem in the clinical treatment of breast cancer.In order to better treat TNBC clinically,it is a very urgent task to explore the mechanism of TNBC resistance in basic breast cancer research.Pregnane X receptor(PXR)is a nuclear receptor whose main biological function is to participate in the metabolism,transport and clearance of allobiological agents in PXR.PXR plays an important role in drug metabolism and clearance,and PXR is highly expressed in tumor tissues of TNBC patients,which is related to the prognosis of breast cancer patients.This reviews synthesized the important role of PXR in the process of high drug resistance to TNBC chemotherapeutic drugs and related research progress.
基金jointly supported by the Key Research and Development Plan of Jiangsu Province,China (Grant No. BE2020318-2)the National Natural Science Foundation of China (Grant No. U19A2026)。
文摘Zinc(Zn) is an essential trace mineral that is required for plant growth and development. A number of protein transporters, which are involved in Zn uptake, translocation and distribution, are finely regulated to maintain Zn homeostasis in plant. In this study, we functionally characterized an ATP-binding cassette(ABC) transporter gene, OsPDR7, which is involved in Zn homeostasis. Os PDR7 encodes a plasma membrane-localized protein that is expressed mainly in the exodermis and xylem in the rice root.ospdr7 mutants resulted in higher Zn accumulation compared with the wild type. Heterogeneous expression of OsPDR7 in a yeast mutant rescued the Zn-deficiency phenotype, implying transport activity of OsPDR7 to Zn in yeast. However, no ZIP genes except for OsZIP9 showed change in expression profile in the ospdr7 mutants, which suggested that OsPDR7 maintains cellular Zn homeostasis through regulating Os ZIP9 expression. RNA-Seq analysis further revealed a set of differentially expressed genes between the wild type and ospdr7 mutants that allowed us to propose a possible OsPDR7-associated signaling network involving transporters, hormone responsive genes, and transcription factors. Our results revealed a novel transporter involved in the regulation of Zn homeostasis and will pave the way toward a better understanding of the fine-tuning of gene expression in the network of transporter genes.
文摘The reuse of dichlorodiphenyltrichloroethane(DDT) as an indoor residual spray was permitted by the World Health Organization in 2007, and approximately 14 countries still use DDT to control disease vectors. The extensive exposure of insects to DDT has resulted in the emergence of DDT resistance, especially in mosquitoes, and the mechanism for this resistance in mosquitoes has been widely reported. Spraying can also introduce DDT directly into surface water, and DDT can subsequently accumulate in microorganisms, but the mechanism for the resistance to DDT degradation in microorganisms is unclear. Using whole-genome microarray analysis, we detected an abcb15 gene that was up-regulated in a specific manner by DDT treatment in T. thermophile. The deduced ABCB15 peptide sequence had two transmembrane domains(TMDs) and two nucleotide-binding domains(NBDs) to form the structure TMD-NBD-TMD-NBD, and each NBD contained three conserved motifs: Walker-A, C-loop, and Walker-B, which indicated the T. thermophila abcb15 was a typical ABC transporter gene. The expression of ABCB15 fused with a C-terminal green fluorescent protein was found to be on the periphery of the cell, suggesting that ABCB15 was a membrane pump protein. In addition, cells with abcb15 partially knocked down(abcb15-KD) grew slower than wild-type cells in the presence of 256 mg L-1 DDT, indicating the tolerance of abcb15-KD strain to DDT exposure was decreased. Thus, we suggest that in Tetrahymena, the membrane pump protein encoded by ABCT gene abcb15 can enhance the tolerance to DDT and protect cells from this exogenous toxin by efficiently pumping it to the extracellular space.
