The Guanine nucleotide exchange factor Vav2（Vav2） is a member of the Vav family that serves as an important regulators for the Rho family of Ras-related GTPases. In the current study, an ortholog（Lj-Vav2） of Vav2 ...The Guanine nucleotide exchange factor Vav2（Vav2） is a member of the Vav family that serves as an important regulators for the Rho family of Ras-related GTPases. In the current study, an ortholog（Lj-Vav2） of Vav2 was identified in the lamprey（Lampetra japonica）. To elucidate the phylogenetic relationship of Vav2, the metazoan genome databases were analyzed to mine the ortholog of Vav. It was found that Vav2 genes were only existed in vertebrates and Lj-Vav2 was the original one found in agnathans. The evolutionary dynamics of conserved motifs of Vav2 were explored using combined amino acid sequence as markers, and it is revealed that the Calponin homology（CH） domain, Dbl-homologous（DH） domain, Pleckstrin homology（PH） domain, Cysteine-rich（C1）domains, Src homology 3（SH3） domains and Src homology 2（SH2） domain were conserved throughout the Vav2 gene family in vertebrates during gene evolution. Relative quantitative real-time PCR analysis showed that the LjVav2 was distributed in the heart, kidney, supraneural myeloid body, liver, gill and lymphocyte-like cells. The LjVav2 was found to be expressed in these tissues, and the level of which was upregulated in lymphocyte-like cells after the animal was stimulated with LPS. These results indicated that the Lj-Vav2 might be involved in the immune response of lymphocyte-like cells in lamprey. Meanwhile, our findings provided a foundation for further investigation of the function of Lj-Vav2 in the primary vertebrate.展开更多
In flowering plants, male gametes are delivered to female gametophytes by pollen tubes. Although it is important for sexual plant reproduction, little is known about the genetic mechanism that controls pollen germinat...In flowering plants, male gametes are delivered to female gametophytes by pollen tubes. Although it is important for sexual plant reproduction, little is known about the genetic mechanism that controls pollen germination and pollen tube growth. Here we report the identification and characterization of two novel mutants, gnom-like 2-1 （gnl2-1） and gn12-2 in Arabidopsis thaliana, in which the pollen grains failed to germinate in vitro and in vivo. GNL2 encodes a protein homologous to the adenosine diphosphate-ribosylation factor-guanine nucleotide exchange factors, GNOM and GNL1 that are involved in endosomal recycling and endoplasmic reticulum-Golgi vesicular trafficking. It was prolifically expressed in pollen grains and pollen tubes. The results of the present study suggest that GNL2 plays an important role in pollen germination.展开更多
Uncontrolled high blood pressure is a major risk factor for heart attack, stroke, and kidney failure and contributes to an estimated 25% of deaths worldwide. Despite numerous treatment options, estimates project that ...Uncontrolled high blood pressure is a major risk factor for heart attack, stroke, and kidney failure and contributes to an estimated 25% of deaths worldwide. Despite numerous treatment options, estimates project that reasonable blood pressure(BP) control is achieved in only about half of hypertensive patients. Improvements in the detection and management of hypertension will undoubtedly be accomplished through a better understanding of the complex etiology of this disease and a more comprehensive inventory of the genes and genetic variants that influence BP regulation. Recent studies(primarily in pre-clinical models) indicate that the small GTPase Rho A and its downstream target, Rho kinase, play an important role in regulating BP homeostasis. Herein, we summarize the underlying mechanisms and highlight signaling pathways and regulators that impart tight spatial-temporal control of Rho A activity. We also discuss known allelic variations in the Rho A pathway and consider how these polymorphisms may affect genetic risk for hypertension and its clinical manifestations. Finally, we summarize the current(albeit limited) clinical data on the efficacy of targeting the Rho A pathway in hypertensive patients.展开更多
Guanine nucleotide exchange factors(GEFs)and guanine nucleotide-dissociation inhibitors(GDIs)regulate small GTPase proteins,which function as molecular switches in various signaling pathways,but their identification a...Guanine nucleotide exchange factors(GEFs)and guanine nucleotide-dissociation inhibitors(GDIs)regulate small GTPase proteins,which function as molecular switches in various signaling pathways,but their identification and functions in plants are not well understood.Using in-silico analysis and transgenic approaches,respectively,we dissected the evolutionary relationships and functions of all GEF and GDI genes in rice.Intron-exon distribution and phylogenetic analyses identified 30 GEF and 10 GDI genes in rice that shared close evolutionary relationships with other eukaryotes.Tissue-specific expression and co-expression analyses revealed that phylogenetically related genes had similar expression patterns.GEF and GDI genes were highly expressed in panicles,hulls,and stamens.Co-expression network analysis identified panicle and stamen-specific modules of co-expressed genes in both families.Mapping of these genes in known protein interactomes further identified two and one small G-protein sub-networks.A mutant library of GEF and GDI families was constructed by CRISPR knockout of each gene,and their genotypes and phenotypes were confirmed.Phenotype changes occurred with the mutation of only three genes(OsGEF5,OsGDI1,and OsGEF3).OsGEF5 and OsGDI1 single mutants exhibited significantly reduced height and longer and thinner grains,whereas OsGEF3 mutants had reduced grain length compared to the wild type.Haplotype and eGWAS analyses showed that natural variations in the three genes affected gene expression in reproductive tissues that were significantly associated with the phenotypic variation.BiFC assays demonstrated that GDI1 and GEF3 interacted with grain-size protein GS3,pointing to a role of these genes in the regulation of grain size and plant architecture connected to heterotrimeric G-proteins in rice.展开更多
基金The National Basic Research Program of China(973 Program)under contract No.2013CB835304the National Marine Public Projects under contract No.201305016+2 种基金the National Natural Science Foundation of China(General Program)under contract No.31601865the Dalian Science and Technology Program under contract No.2013E11SF056the Education Department of the General Scientific Research Project under contract No.L201683651
文摘The Guanine nucleotide exchange factor Vav2（Vav2） is a member of the Vav family that serves as an important regulators for the Rho family of Ras-related GTPases. In the current study, an ortholog（Lj-Vav2） of Vav2 was identified in the lamprey（Lampetra japonica）. To elucidate the phylogenetic relationship of Vav2, the metazoan genome databases were analyzed to mine the ortholog of Vav. It was found that Vav2 genes were only existed in vertebrates and Lj-Vav2 was the original one found in agnathans. The evolutionary dynamics of conserved motifs of Vav2 were explored using combined amino acid sequence as markers, and it is revealed that the Calponin homology（CH） domain, Dbl-homologous（DH） domain, Pleckstrin homology（PH） domain, Cysteine-rich（C1）domains, Src homology 3（SH3） domains and Src homology 2（SH2） domain were conserved throughout the Vav2 gene family in vertebrates during gene evolution. Relative quantitative real-time PCR analysis showed that the LjVav2 was distributed in the heart, kidney, supraneural myeloid body, liver, gill and lymphocyte-like cells. The LjVav2 was found to be expressed in these tissues, and the level of which was upregulated in lymphocyte-like cells after the animal was stimulated with LPS. These results indicated that the Lj-Vav2 might be involved in the immune response of lymphocyte-like cells in lamprey. Meanwhile, our findings provided a foundation for further investigation of the function of Lj-Vav2 in the primary vertebrate.
基金Supported by the National Natural Science Foundation of China (30530060)the State Key Basic Research and Development Plan of China(2007CB108700)the Ministry of Education (111 project numberedB06003)
文摘In flowering plants, male gametes are delivered to female gametophytes by pollen tubes. Although it is important for sexual plant reproduction, little is known about the genetic mechanism that controls pollen germination and pollen tube growth. Here we report the identification and characterization of two novel mutants, gnom-like 2-1 （gnl2-1） and gn12-2 in Arabidopsis thaliana, in which the pollen grains failed to germinate in vitro and in vivo. GNL2 encodes a protein homologous to the adenosine diphosphate-ribosylation factor-guanine nucleotide exchange factors, GNOM and GNL1 that are involved in endosomal recycling and endoplasmic reticulum-Golgi vesicular trafficking. It was prolifically expressed in pollen grains and pollen tubes. The results of the present study suggest that GNL2 plays an important role in pollen germination.
基金Supported by the National Heart,Lung,and Blood Institute,National Institutes of Health to Taylor JM,Nos.HL-081844 and HL-071054the Muscular Dystrophy Association to Taylor JM,No.MDA255577
文摘Uncontrolled high blood pressure is a major risk factor for heart attack, stroke, and kidney failure and contributes to an estimated 25% of deaths worldwide. Despite numerous treatment options, estimates project that reasonable blood pressure(BP) control is achieved in only about half of hypertensive patients. Improvements in the detection and management of hypertension will undoubtedly be accomplished through a better understanding of the complex etiology of this disease and a more comprehensive inventory of the genes and genetic variants that influence BP regulation. Recent studies(primarily in pre-clinical models) indicate that the small GTPase Rho A and its downstream target, Rho kinase, play an important role in regulating BP homeostasis. Herein, we summarize the underlying mechanisms and highlight signaling pathways and regulators that impart tight spatial-temporal control of Rho A activity. We also discuss known allelic variations in the Rho A pathway and consider how these polymorphisms may affect genetic risk for hypertension and its clinical manifestations. Finally, we summarize the current(albeit limited) clinical data on the efficacy of targeting the Rho A pathway in hypertensive patients.
基金supported by the National Natural Science Foundation of China(32072042,31821005,32000370)Ten-Thousand Talents Programs,Fundamental Research Funds for the Central Universities(2662020SKPY006)+1 种基金Wuhan Applied Foundational Frontier Project(2020020601012257)Hubei Hongshan Laboratory(2021hszd005).
文摘Guanine nucleotide exchange factors(GEFs)and guanine nucleotide-dissociation inhibitors(GDIs)regulate small GTPase proteins,which function as molecular switches in various signaling pathways,but their identification and functions in plants are not well understood.Using in-silico analysis and transgenic approaches,respectively,we dissected the evolutionary relationships and functions of all GEF and GDI genes in rice.Intron-exon distribution and phylogenetic analyses identified 30 GEF and 10 GDI genes in rice that shared close evolutionary relationships with other eukaryotes.Tissue-specific expression and co-expression analyses revealed that phylogenetically related genes had similar expression patterns.GEF and GDI genes were highly expressed in panicles,hulls,and stamens.Co-expression network analysis identified panicle and stamen-specific modules of co-expressed genes in both families.Mapping of these genes in known protein interactomes further identified two and one small G-protein sub-networks.A mutant library of GEF and GDI families was constructed by CRISPR knockout of each gene,and their genotypes and phenotypes were confirmed.Phenotype changes occurred with the mutation of only three genes(OsGEF5,OsGDI1,and OsGEF3).OsGEF5 and OsGDI1 single mutants exhibited significantly reduced height and longer and thinner grains,whereas OsGEF3 mutants had reduced grain length compared to the wild type.Haplotype and eGWAS analyses showed that natural variations in the three genes affected gene expression in reproductive tissues that were significantly associated with the phenotypic variation.BiFC assays demonstrated that GDI1 and GEF3 interacted with grain-size protein GS3,pointing to a role of these genes in the regulation of grain size and plant architecture connected to heterotrimeric G-proteins in rice.
