转录因子与microRNA在基因表达调控中的功能联系及差异

转录因子和微RNA(microRNA)是最大的两类反式作用因子,它们是基因表达调控的重要调控因子.它们协调发挥调控作用,精细调控基因的表达,在细胞分化和动物生长发育过程中发挥重要的作用.随着对转录因子和microRNA研究的深入,人们发现转录因子和microRNA在基因表达调控网络中关系紧密,它们的分子作用机制有许多相似之处,两者都通过各自的顺式作用元件调控基因表达,且作用的方式类似.但转录因子和microRNA也存在不同之处,转录因子既可以激活基因表达,也可抑制基因表达,而microRNA主要是抑制基因表达.另外,转录因子调控区的复杂性一般高于microRNA的调控区域.本文综述了转录因子和microRNA的异同点,并提出了未来转录因子和microRNA的研究方向.     

植物转录因子最新研究方法

转录因子可以调控众多下游基因的表达,在植物的生长发育、代谢及对外界环境的反应中起着重要作用。我们结合近年来植物转录因子的研究进展,归纳分析了高等植物转录因子研究的主要策略和最新的技术方法,并从生物信息学分析、瞬间转化技术的应用、突变体表型分析及调控网络等几个方面进行了全面阐述,为植物转录因子的预测、功能鉴定及靶基因分析等相关研究提供理论和方法的参考。     

MYB类转录因子对花药和花粉发育的调控途径

花药发育和花粉形成的各个步骤由众多基因控制,一些转录因子通过调控花药发育相关基因的表达,是功能性花粉形成的关键因子。MYB类转录因子作为植物中最大的转录因子家族,是其中非常重要的一类转录因子。该文结合近年来国内外有关被子植物花粉发育相关MYB转录因子在花药发育和花粉形成的调控途径,包括绒毡层发育、胼胝质的沉积和降解、光合产物的运输、花药的开裂以及雄配子体形成过程中所起的重要作用等方面的研究进展,重点对MYB类转录因子通过形成对绒毡层发育、同化物分配、苯丙烷物质代谢等相关靶位基因的控制网络,转录调控植物花粉发育和花药开裂过程等研究进行综述讨论。     

Harpin_(Xoo)及其功能域片段启动病原物诱导性启动子在转基因拟南芥中的活性(英文)

从烟草(Mcotiana tabacum L.)中克隆了3个病原物诱导性启动子PPP1、PPP2和PPP3,它们都含受细菌诱导的反应元件PPP1和PPP2,另外含有受生物激发子及水杨酸(SA)诱导的元件;PPP1内部还含串联重复的两段111bp的序列,而在PPP2中,这个重复序列中的一个111 bp的片段被定点删除。分别构建了含这三个启动子及花椰菜花叶病毒35S启动子的转化单元,用它们分别转化拟南芥(Arabidopsis thaliana L.),获得了转基因植株。PCR证明,几个启动子和所带的gus基因(uidA)已经整合到拟南芥基因组中。用青枯病菌接种转基因第二代植株,组织染色表明三个PPP启动子在拟南芥中都可以受青枯病菌诱导,说明克隆的PPP启动子是有活性的。随后分别用SA、来自水稻白叶枯病菌的蛋白质激发子halpinXoo以及hatpinXoo的3个具有不同功能的片段DEG(促进生长)、DIR(诱导抗虫)、DPR(诱导抗病)喷雾处理转基因植株,通过GUS的荧光定量分析,检测了启动子的活性。结果显示,青枯病菌诱导的PPP1、PPP2和PPP3活性分别为35S启动子活性的53、39和25倍。PPP1和PPP2可以受SA、harpinXoo、DEG、DIR和DPR的诱导,而PPP3则不能。这些结果说明了有关元件的可能作用。另外,PPP1的活性比PPP2高3倍,表明111bp的重复序列可以影响启动子活性水平。     

植物非生物胁迫诱导启动子顺式元件及转录因子研究进展

顺式作用元件(cix-acting element)是与结构基因串联的特定DNA序列,是转录因子的结合位点,它们通过与转录因子结合调控基因转录的精确起始和转录效率,在植物基因表达调控过程中起着重要的作用.非生物胁迫诱导基因的表达受其上游启动子顺式作用元件及转录因子的调控,目前已发现了多种与非生物胁迫相关的顺势作用元件及转录因子,如DRE元件及DREB类转录因子、MYB元件及MYB类转录因子、GT-1元件及GT-1类转录因子等.顺式作用元件及转录因子的研究对研究植物非生物胁迫相关基因的表达调控具有重要意义,综述植物非生物胁迫诱导启动子功能元件及转录因子的研究进展.     

HarpinXoo及其功能域片段启动病原物诱导性启动子在转基因拟南芥中的活性

从烟草(Nicotiana tabacum L.)中克隆了3个病原物诱导性启动子PPP1、PPP2和PPP3,它们都含受细菌诱导的反应元件PPP1和PPP2中,另含有受生物激发子及水杨酸(SA)的诱导元件;PPP1内部还含重复的两段111bp的序列,而在PPP2K ,这个重复序列号中的一个111bpr的片段被定点删除.分别构建了含这三个启动子及花椰菜花叶病毒35S启动子的转化单元,用它们分别转化拟南芥(Arabidopsis thaliana L.)获得了转基因植株.PCR证明,几个启动子和所带的gus基因(uidA)已经整合到拟南芥基因组中.用青枯病菌接种转基因第二代植株,组织染色表明三个PPP启动子在拟南芥中都可以受青枯病菌诱导,说明克隆的PPP启动子是活性的.随后分别用SA、来自水稻白叶枯病菌的蛋白质激发子harpinx00以及harpinx00的3个具有不同功能的片段DEG(促进生长)、DIR(诱导抗病)喷雾处理转基因植株,通过GUS 的荧光定量分析,检测了启动子的活性.结果显示,表枯病菌诱导PPP1、PPP2和PPP3活性分别为35S启动子活性的53、39和25倍.PPP1和PPP2可以受SA、harpinx00、DEG、DIR和DPR的诱导,而PPP3则不能.这些结果说明了有关元件的可能作用.另外,PPP1 的活性比PPP2高3倍,表明11bp重复序列可以影响启动子活性水平.     

Evolutionary pattern of the regulatory network for flower development:Insights gained from a comparison of two Arabidopsis species

Previous studies on Arabidopsis thaliana and other model plants have indicated that the development of a flower is controlled by a regulatory network composed of genes and the interactions among them.Studies on the evolution of this network will therefore help understand the genetic basis that underlies flower evolution.In this study,by reviewing the most recent published work,we added 31 genes into the previously proposed regulatory network for flower development.Thus,the number of genes reached 60.We then compared the composition,structure,and evolutionary rate of these genes between A.thaliana and one of its allies,A.lyrata.We found that two genes (FLC and MAF2) show 1∶ 2 and 2∶ 2 relationships between the two species,suggesting that they have experienced independent,post-speciation duplications.Of the remaining 58 genes,35 (60.3％) have diverged in exon-intron structure and,consequently,code for proteins with different sequence features and functions.Molecular evolutionary analyses further revealed that,although most floral genes have evolved under strong purifying selection,some have evolved under relaxed or changed constraints,as evidenced by the elevation of nonsynonymous substitution rates and/or the presence of positively selected sites.Taken together,these results suggest that the regulatory network for flower development has evolved rather rapidly,with changes in the composition,structure,and functional constraint of genes,as well as the interactions among them,being the most important contributors.     

Evolutionary pattern of the regulatory network for flower development: Insights gained from a comparison of two Arabidopsis species

Abstract Previous studies on Arabidopsis thaliana and other model plants have indicated that the development of a flower is controlled by a regulatory network composed of genes and the interactions among them. Studies on the evolution of this network will therefore help understand the genetic basis that underlies flower evolution. In this study, by reviewing the most recent published work, we added 31 genes into the previously proposed regulatory network for flower development. Thus, the number of genes reached 60. We then compared the composition, structure, and evolutionary rate of these genes between A. thaliana and one of its allies, A. lyrata. We found that two genes (FLC and MAF2) show 1: 2 and 2: 2 relationships between the two species, suggesting that they have experienced independent, post‐speciation duplications. Of the remaining 58 genes, 35 (60.3%) have diverged in exon–intron structure and, consequently, code for proteins with different sequence features and functions. Molecular evolutionary analyses further revealed that, although most floral genes have evolved under strong purifying selection, some have evolved under relaxed or changed constraints, as evidenced by the elevation of nonsynonymous substitution rates and/or the presence of positively selected sites. Taken together, these results suggest that the regulatory network for flower development has evolved rather rapidly, with changes in the composition, structure, and functional constraint of genes, as well as the interactions among them, being the most important contributors.