Pollen tube growth is an essential step during flowering plant reproduction, whose growth depends on a population of dynamic apical actin filaments. Apical actin filaments were thought to be involved in the regu- lati...Pollen tube growth is an essential step during flowering plant reproduction, whose growth depends on a population of dynamic apical actin filaments. Apical actin filaments were thought to be involved in the regu- lation of vesicle fusion and targeting in the pollen tube. However, the molecular mechanisms that regulate the construction of apical actin structures in the pollen tube remain largely unclear. Here, we identify profilin as an important player in the regulation of actin polymerization at the apical membrane in the pollen tube. Downregulation of profilin decreased the amount of filamentous actin and induced disorganization of apical actin filaments, and reduced tip-directed vesicle transport and accumulation in the pollen tube. Direct visualization of actin dynamics revealed that the elongation of actin filaments originating at the apical membrane decreased in profilin mutant pollen tubes. Mutant profilin that is defective in binding poly-L-proline only partially rescues the actin polymerization defect in profilin mutant pollen tubes, although it fully rescues the actin turnover phenotype. We propose that profilin controls the construction of actin structures at the pollen tube tip, presumably by favoring formin-mediated actin polymerization at the apical membrane.展开更多
Profilin has recently been identified as an actin-binding protein in higher plants. A cDNA clone (designated Repro) encoding profilin gene was isolated from rapeseed ( Brassica napus L. cv. canadian Tween) using RT-PC...Profilin has recently been identified as an actin-binding protein in higher plants. A cDNA clone (designated Repro) encoding profilin gene was isolated from rapeseed ( Brassica napus L. cv. canadian Tween) using RT-PCR technique. Sequence analysis showed 82% similarity to Zea mays L. ZmPro3, 85% to Arabidopsis AthPRF1, 82% to Nicotiana tabacum L. NTPRO, 81% to Oryza sativa L. profilin A. A new full-length cDNA was obtained by 5'-RACE and 3'-RACE techniques. Sequence analysis showed that the size of full-length cDNA is 672 bp which contains a major open reading frame of 134 amino, acids, 5' and 3' untranslated regions and a long Poly (A) tail. Northern blot analysis showed that the profilin gene is a pollen and anther specific gene.展开更多
Formins are conserved regulators of actin cytoskeletal organization and dynamics that have been impli- cated to be important for cell division and cell polarity. The mechanism by which diverse formins regulate actin d...Formins are conserved regulators of actin cytoskeletal organization and dynamics that have been impli- cated to be important for cell division and cell polarity. The mechanism by which diverse formins regulate actin dynamics in plants is still not well understood. Using in vitro single-molecule imaging technology, we directly observed that the FH1-FH2 domain of an Arabidopsis thaliana formin, AtFH14, processively at- taches to the barbed end of actin filaments as a dimer and slows their elongation rate by 90%. The attach- ment persistence of FH1-FH2 is concentration dependent. Furthermore, by use of the triple-color total internal reflection fluorescence microscopy, we found that ABP29, a barbed-end capping protein, com- petes with FH1-FH2 at the filament barbed end, where its binding is mutually exclusive with AtFH14. In the presence of different plant profilin isoforms, FH1-FH2 enhances filament elongation rates from about 10 to 42 times. Filaments buckle when FH1-FH2 is anchored specifically to cover slides, further indicating that AtFH 14 moves processively on the elongating barbed end. At high concentration, AtFH 14 bundles actin filaments randomly into antiparallel or parallel spindle-like structures; however, the FH1-FH2-mediated bundles become thinner and longer in the presence of plant profilins. This is the direct demonstration of a processive formin from plants. Our results also illuminate the molecular mechanism of AtFH14 in regulating actin dynamics via association with profilin.展开更多
Growing evidence indicates that actin cytoskeleton is involved in plant innate immune responses, but the functional mechanism remains largely unknown. Here, we investigated the behavior of a cotton profilin gene （GhP...Growing evidence indicates that actin cytoskeleton is involved in plant innate immune responses, but the functional mechanism remains largely unknown. Here, we investigated the behavior of a cotton profilin gene （GhPFN2） in response to Verticillium dahliae invasion, and evaluated its contribution to plant defense against this soil-borne fungal pathogen. GhPFN2 expression was up-regulated when cotton root was inoculated with V. dahliae, and the actin architecture was reorganized in the infected root cells, with a clear increase in the density of filamentous actin and the extent of actin btmdling. Compared to the wild type, GhPFN2-overexpressing cotton plants showed enhanced protection against V. dahliae infection and the actin cytoskeleton organization in root epidermal cells was clearly altered, which phenocopied that of the wild-type （WT） root cells challenged with V. dahliae. These results provide a solid line of evidence important for defense against V. dahliae infection. showing that actin cytoskeleton reorganization involving GhPFN2 is展开更多
Objective:To explore the mechanism of Profilin-1 in regulating eNOS/NO pathway and its role in the development of myocardial hypertrophy.Methods:Spontaneously hypertensive rats(SHR) aged 5 weeks were injected with dif...Objective:To explore the mechanism of Profilin-1 in regulating eNOS/NO pathway and its role in the development of myocardial hypertrophy.Methods:Spontaneously hypertensive rats(SHR) aged 5 weeks were injected with different adenovirus vectors to induce Profilin-1expression knockdown(SHR-I) or over express(SHR-H) or to use as control(SHR-C).All these treatment were compared with Wistar-Kyoto rats(SKY) treated with control adenovirus vectors(WKY-C).The same injection was executed at the sixth week during the experiment of 12 weeks.After experiment,the left ventricular weight-to-heart weight ratio(LVW/HW)and left ventricular long axis(LVLA) were measured.Meanwhile.NO contents in blood and myocardium,Profilin-1,eNOS and Caveolin-3 niRNA and protein levels and phosphorylated eNOS(P-eNOS) protein level in myocardium were determined.Results:Compared with WKY-C group,the SHR-C group was statistically higher in LVW/HW(0.79±0.03).LVLA(11.82±0.58 mm) and Profilin-1 niRNA and prolein level(P<0.05).but lower in NO content[(18.63±6.23) μmol/L| in blood and[(2.71±0.17) μmol/L]in myocardium).eNOS activity and Caveolin-3 expression(P<0.05).The over expressing Profilin-1 led SHR-H group to a higher value of LVW/HW[(0.93±0.03) mm and LVLA(14.17±0.69) mm]in comparison with SHR-C group(P<0.05).and to a lower value of NO content(in myocardium).eNOS activity and Caveolin-3 expression(P<0.05):however,this phenomenon was reversed by the knockdown Profilin-1 expression(SHR-I group).Conclusions:Profilin-1 expression,being negative in regulating Caveolin-3 expression and eNOS/NO pathway activity,promotes the development of myocardial hypertrophy which can be reversed by Profilin-1 silencing.展开更多
文摘Pollen tube growth is an essential step during flowering plant reproduction, whose growth depends on a population of dynamic apical actin filaments. Apical actin filaments were thought to be involved in the regu- lation of vesicle fusion and targeting in the pollen tube. However, the molecular mechanisms that regulate the construction of apical actin structures in the pollen tube remain largely unclear. Here, we identify profilin as an important player in the regulation of actin polymerization at the apical membrane in the pollen tube. Downregulation of profilin decreased the amount of filamentous actin and induced disorganization of apical actin filaments, and reduced tip-directed vesicle transport and accumulation in the pollen tube. Direct visualization of actin dynamics revealed that the elongation of actin filaments originating at the apical membrane decreased in profilin mutant pollen tubes. Mutant profilin that is defective in binding poly-L-proline only partially rescues the actin polymerization defect in profilin mutant pollen tubes, although it fully rescues the actin turnover phenotype. We propose that profilin controls the construction of actin structures at the pollen tube tip, presumably by favoring formin-mediated actin polymerization at the apical membrane.
文摘Profilin has recently been identified as an actin-binding protein in higher plants. A cDNA clone (designated Repro) encoding profilin gene was isolated from rapeseed ( Brassica napus L. cv. canadian Tween) using RT-PCR technique. Sequence analysis showed 82% similarity to Zea mays L. ZmPro3, 85% to Arabidopsis AthPRF1, 82% to Nicotiana tabacum L. NTPRO, 81% to Oryza sativa L. profilin A. A new full-length cDNA was obtained by 5'-RACE and 3'-RACE techniques. Sequence analysis showed that the size of full-length cDNA is 672 bp which contains a major open reading frame of 134 amino, acids, 5' and 3' untranslated regions and a long Poly (A) tail. Northern blot analysis showed that the profilin gene is a pollen and anther specific gene.
基金国家自然科学基金(30871752,30570421)The International Science and Technology(ISAT)Linkages Fund,Royal Society of New Zealand(ISATB09-33)+1 种基金广东省科技重点专项(2003A3080502)教育部留学回国人员科研启动基金
文摘Formins are conserved regulators of actin cytoskeletal organization and dynamics that have been impli- cated to be important for cell division and cell polarity. The mechanism by which diverse formins regulate actin dynamics in plants is still not well understood. Using in vitro single-molecule imaging technology, we directly observed that the FH1-FH2 domain of an Arabidopsis thaliana formin, AtFH14, processively at- taches to the barbed end of actin filaments as a dimer and slows their elongation rate by 90%. The attach- ment persistence of FH1-FH2 is concentration dependent. Furthermore, by use of the triple-color total internal reflection fluorescence microscopy, we found that ABP29, a barbed-end capping protein, com- petes with FH1-FH2 at the filament barbed end, where its binding is mutually exclusive with AtFH14. In the presence of different plant profilin isoforms, FH1-FH2 enhances filament elongation rates from about 10 to 42 times. Filaments buckle when FH1-FH2 is anchored specifically to cover slides, further indicating that AtFH 14 moves processively on the elongating barbed end. At high concentration, AtFH 14 bundles actin filaments randomly into antiparallel or parallel spindle-like structures; however, the FH1-FH2-mediated bundles become thinner and longer in the presence of plant profilins. This is the direct demonstration of a processive formin from plants. Our results also illuminate the molecular mechanism of AtFH14 in regulating actin dynamics via association with profilin.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB11040600)the National Natural Science Foundation of China(31671278)the State Key Laboratory of Plant Genomics of China(2015B0129-02)
文摘Growing evidence indicates that actin cytoskeleton is involved in plant innate immune responses, but the functional mechanism remains largely unknown. Here, we investigated the behavior of a cotton profilin gene （GhPFN2） in response to Verticillium dahliae invasion, and evaluated its contribution to plant defense against this soil-borne fungal pathogen. GhPFN2 expression was up-regulated when cotton root was inoculated with V. dahliae, and the actin architecture was reorganized in the infected root cells, with a clear increase in the density of filamentous actin and the extent of actin btmdling. Compared to the wild type, GhPFN2-overexpressing cotton plants showed enhanced protection against V. dahliae infection and the actin cytoskeleton organization in root epidermal cells was clearly altered, which phenocopied that of the wild-type （WT） root cells challenged with V. dahliae. These results provide a solid line of evidence important for defense against V. dahliae infection. showing that actin cytoskeleton reorganization involving GhPFN2 is
基金funded by Key Disciplines Group Construction Project of Pudong Health Bureau of Shanghai(No.PWZxq2014-01)Natural Science Foundation of China(No.81401428)the fund of the Academic Leaders Training Program of Pudong Health Bureau of Shanghai(No.PWRd2013-02)
文摘Objective:To explore the mechanism of Profilin-1 in regulating eNOS/NO pathway and its role in the development of myocardial hypertrophy.Methods:Spontaneously hypertensive rats(SHR) aged 5 weeks were injected with different adenovirus vectors to induce Profilin-1expression knockdown(SHR-I) or over express(SHR-H) or to use as control(SHR-C).All these treatment were compared with Wistar-Kyoto rats(SKY) treated with control adenovirus vectors(WKY-C).The same injection was executed at the sixth week during the experiment of 12 weeks.After experiment,the left ventricular weight-to-heart weight ratio(LVW/HW)and left ventricular long axis(LVLA) were measured.Meanwhile.NO contents in blood and myocardium,Profilin-1,eNOS and Caveolin-3 niRNA and protein levels and phosphorylated eNOS(P-eNOS) protein level in myocardium were determined.Results:Compared with WKY-C group,the SHR-C group was statistically higher in LVW/HW(0.79±0.03).LVLA(11.82±0.58 mm) and Profilin-1 niRNA and prolein level(P<0.05).but lower in NO content[(18.63±6.23) μmol/L| in blood and[(2.71±0.17) μmol/L]in myocardium).eNOS activity and Caveolin-3 expression(P<0.05).The over expressing Profilin-1 led SHR-H group to a higher value of LVW/HW[(0.93±0.03) mm and LVLA(14.17±0.69) mm]in comparison with SHR-C group(P<0.05).and to a lower value of NO content(in myocardium).eNOS activity and Caveolin-3 expression(P<0.05):however,this phenomenon was reversed by the knockdown Profilin-1 expression(SHR-I group).Conclusions:Profilin-1 expression,being negative in regulating Caveolin-3 expression and eNOS/NO pathway activity,promotes the development of myocardial hypertrophy which can be reversed by Profilin-1 silencing.
