EREBP/AP2-type proteins are members of a large DNA binding protein (DBP) family found in plants. Some members like APETALA2 and AtDREB/CBF can regulate flower development and response to environmental stresses, respec...EREBP/AP2-type proteins are members of a large DNA binding protein (DBP) family found in plants. Some members like APETALA2 and AtDREB/CBF can regulate flower development and response to environmental stresses, respectively. To characterize transcription factors involved in plant responses to salt stress, we constructed cDNA library from salt-treated halophyte (Atriplex hortensis) and isolated a novel gene encoding EREBP/AP2-type protein from this library. This cDNA contained an ORF of 723 bp and a long 3'-Untranslated-Region (UTR) of 655 bp. The deduced amino acid sequence showed one conserved DNA binding domain of EREBP/AP2, thus the corresponding gene was named AhDREB1 with a calculated molecular mass of 26.1 kD. AhDREB1 under the control of CaMV 35S promoter was then transformed into tobacco and nine independent transgenic lines were obtained and subjected to long term salt stress. The results suggested that overexpression of AhDREB1 improved the salt tolerance in transgenic tobacco through functioning as a regulatory molecule in response to salt stress. Analysis of Arabidopsis genome in database resulted in dozens of EREBP/AP2-type homologous proteins, of which seven members showed high similarity to AhDREB1. Secondary structure analysis predicted similar arrangement of a-helix in their DNA binding domains.展开更多
AP-2β是转录因子AP-2家族中的重要一员.AP-2是一个与哺乳动物的发育、细胞生长、分化、凋亡和肿瘤发生都有密切联系的重要的转录因子家族.最近的研究表明,AP-2能通过与其他蛋白的相互作用来调控AP-2下游基因的转录活性.采用免疫共沉淀...AP-2β是转录因子AP-2家族中的重要一员.AP-2是一个与哺乳动物的发育、细胞生长、分化、凋亡和肿瘤发生都有密切联系的重要的转录因子家族.最近的研究表明,AP-2能通过与其他蛋白的相互作用来调控AP-2下游基因的转录活性.采用免疫共沉淀结合质谱鉴定的方法筛选与AP-2β相互作用的蛋白.结果筛选到Stomatin like protein2(SLP-2)蛋白可能与AP-2β相互作用.免疫共沉淀实验证实外源过表达和内源的SLP-2蛋白都能与AP-2β蛋白相互作用.而且,细胞免疫荧光实验发现外源表达的Myc-AP-2β蛋白与内源的SLP-2蛋白在MCF-7细胞的胞质中有共定位.此外,免疫印记实验结果表明过表达SLP-2能上调AP-2β的蛋白水平,这就表明SLP-2与AP-2β相互作用后,SLP-2可能使AP-2β蛋白更稳定.这些研究结果为进一步研究这两个基因的功能提供了新的切入点.展开更多
Grain size is an important determinant of grain yield in rice.Although dozens of grain size genes have been reported,the molecular mechanisms that control grain size remain to be fully clarified.Here,we report the clo...Grain size is an important determinant of grain yield in rice.Although dozens of grain size genes have been reported,the molecular mechanisms that control grain size remain to be fully clarified.Here,we report the cloning and characterization of GR5(GRAIN ROUND 5),which is allelic to SMOS1/SHB/RLA1/NGR5 and en-codes an AP2 transcription factor.GR5 acts as a transcriptional activator and determines grain size by influencing cell proliferation and expansion.We demonstrated that GR5 physically interacts withfive Gg subunit proteins(RGG1,RGG2,DEP1,GS3,and GGC2)and acts downstream of the G protein complex.Four downstream target genes of GR5 in grain development(DEP2,DEP3,DRW1,and CyCD5;2)were re-vealed and their core T/CGCAC motif identified by yeast one-hybrid,EMSA,and ChIP–PCR experiments.Our results revealed that GR5 interacts with Gg subunits and cooperatively determines grain size by regu-lating the expression of downstream target genes.Thesefindings provide new insight into the genetic reg-ulatory network of the G protein signaling pathway in the control of grain size and provide a potential target for high-yield rice breeding.展开更多
Amylose content(AC) is the main factor determining the palatability, viscosity, transparency, and digestibility of rice(Oryza sativa)grains. AC in rice grains is mainly controlled by different alleles of the Waxy(Wx) ...Amylose content(AC) is the main factor determining the palatability, viscosity, transparency, and digestibility of rice(Oryza sativa)grains. AC in rice grains is mainly controlled by different alleles of the Waxy(Wx) gene. The AP2/EREBP transcription factor OsEBP89 interacts with the MYC-like protein OsBP5 to synergistically regulate the expression of Wx.Here, we determined that the GLYCOGEN SYNTHASE KINASE 5(OsGSK5, also named SHAGGY-like kinase 41 [OsSK41]) inhibits the transcriptional activation activity of OsEBP89 in rice grains during amylose biosynthesis. The loss of OsSK41 function enhanced Wx expression and increased AC in rice grains. By contrast, the loss of function of OsEBP89 reduced Wx expression and decreased AC in rice grains. OsSK41 interacts with OsEBP89 and phosphorylates four of its sites(Thr-28,Thr-30, Ser-238, and Thr-257), which makes OsEBP89 unstable and attenuates its interaction with OsBP5. Wx promoter activity was relatively weak when regulated by the phosphomimicvariantOsEBP89E–OsBP5but relatively strong when regulated by the nonphosphorylatable variant OsEBP89A–OsBP5.Therefore, OsSK41-mediated phosphorylation of OsEBP89 represents an additional layer of complexity in the regulation of amylose biosynthesis during rice grain development. In addition, our findings provide four possible sites for regulating rice grain AC via precise gene editing.展开更多
文摘EREBP/AP2-type proteins are members of a large DNA binding protein (DBP) family found in plants. Some members like APETALA2 and AtDREB/CBF can regulate flower development and response to environmental stresses, respectively. To characterize transcription factors involved in plant responses to salt stress, we constructed cDNA library from salt-treated halophyte (Atriplex hortensis) and isolated a novel gene encoding EREBP/AP2-type protein from this library. This cDNA contained an ORF of 723 bp and a long 3'-Untranslated-Region (UTR) of 655 bp. The deduced amino acid sequence showed one conserved DNA binding domain of EREBP/AP2, thus the corresponding gene was named AhDREB1 with a calculated molecular mass of 26.1 kD. AhDREB1 under the control of CaMV 35S promoter was then transformed into tobacco and nine independent transgenic lines were obtained and subjected to long term salt stress. The results suggested that overexpression of AhDREB1 improved the salt tolerance in transgenic tobacco through functioning as a regulatory molecule in response to salt stress. Analysis of Arabidopsis genome in database resulted in dozens of EREBP/AP2-type homologous proteins, of which seven members showed high similarity to AhDREB1. Secondary structure analysis predicted similar arrangement of a-helix in their DNA binding domains.
文摘AP-2β是转录因子AP-2家族中的重要一员.AP-2是一个与哺乳动物的发育、细胞生长、分化、凋亡和肿瘤发生都有密切联系的重要的转录因子家族.最近的研究表明,AP-2能通过与其他蛋白的相互作用来调控AP-2下游基因的转录活性.采用免疫共沉淀结合质谱鉴定的方法筛选与AP-2β相互作用的蛋白.结果筛选到Stomatin like protein2(SLP-2)蛋白可能与AP-2β相互作用.免疫共沉淀实验证实外源过表达和内源的SLP-2蛋白都能与AP-2β蛋白相互作用.而且,细胞免疫荧光实验发现外源表达的Myc-AP-2β蛋白与内源的SLP-2蛋白在MCF-7细胞的胞质中有共定位.此外,免疫印记实验结果表明过表达SLP-2能上调AP-2β的蛋白水平,这就表明SLP-2与AP-2β相互作用后,SLP-2可能使AP-2β蛋白更稳定.这些研究结果为进一步研究这两个基因的功能提供了新的切入点.
基金supported by the National Key Research and Development Program of China (2022YFF1002901)the Hainan Yazhou Bay Seed Laboratory (B21HJ0215)+4 种基金the Natural Science Foundation of China (32272109)the Nanfan special project (ZDXM2315)of CAASthe Natural Science Foundation of China (32072048,U2004204)the Qian Qian Academician Workstation,the specific research fund of the Innovation Platform for Academicians of Hainan Province (YSPTZX202303)the Key Research and Development Program of Zhejiang Province (2021C02056).
文摘Grain size is an important determinant of grain yield in rice.Although dozens of grain size genes have been reported,the molecular mechanisms that control grain size remain to be fully clarified.Here,we report the cloning and characterization of GR5(GRAIN ROUND 5),which is allelic to SMOS1/SHB/RLA1/NGR5 and en-codes an AP2 transcription factor.GR5 acts as a transcriptional activator and determines grain size by influencing cell proliferation and expansion.We demonstrated that GR5 physically interacts withfive Gg subunit proteins(RGG1,RGG2,DEP1,GS3,and GGC2)and acts downstream of the G protein complex.Four downstream target genes of GR5 in grain development(DEP2,DEP3,DRW1,and CyCD5;2)were re-vealed and their core T/CGCAC motif identified by yeast one-hybrid,EMSA,and ChIP–PCR experiments.Our results revealed that GR5 interacts with Gg subunits and cooperatively determines grain size by regu-lating the expression of downstream target genes.Thesefindings provide new insight into the genetic reg-ulatory network of the G protein signaling pathway in the control of grain size and provide a potential target for high-yield rice breeding.
基金financially supported by the Innovation Program of Shanghai Municipal Education Commission (2023ZKZD05)the National Natural Science Foundation of China (31971918, 32172043)+1 种基金the Agriculture Research System of Shanghai, China (Grant No. 202203)the Shanghai Science and Technology Innovation Action Plan Project (22N11900200)。
文摘Amylose content(AC) is the main factor determining the palatability, viscosity, transparency, and digestibility of rice(Oryza sativa)grains. AC in rice grains is mainly controlled by different alleles of the Waxy(Wx) gene. The AP2/EREBP transcription factor OsEBP89 interacts with the MYC-like protein OsBP5 to synergistically regulate the expression of Wx.Here, we determined that the GLYCOGEN SYNTHASE KINASE 5(OsGSK5, also named SHAGGY-like kinase 41 [OsSK41]) inhibits the transcriptional activation activity of OsEBP89 in rice grains during amylose biosynthesis. The loss of OsSK41 function enhanced Wx expression and increased AC in rice grains. By contrast, the loss of function of OsEBP89 reduced Wx expression and decreased AC in rice grains. OsSK41 interacts with OsEBP89 and phosphorylates four of its sites(Thr-28,Thr-30, Ser-238, and Thr-257), which makes OsEBP89 unstable and attenuates its interaction with OsBP5. Wx promoter activity was relatively weak when regulated by the phosphomimicvariantOsEBP89E–OsBP5but relatively strong when regulated by the nonphosphorylatable variant OsEBP89A–OsBP5.Therefore, OsSK41-mediated phosphorylation of OsEBP89 represents an additional layer of complexity in the regulation of amylose biosynthesis during rice grain development. In addition, our findings provide four possible sites for regulating rice grain AC via precise gene editing.
