HD-Zip III转录因子家族与植物细胞分化

细胞分化是生物生长发育的重要过程, 受到一系列信号的精确调控。植物特有的转录因子HD-Zip III在细胞分化中发挥了重要作用。该文对HD-Zip III基因类型和结构特点进行了简要介绍, 重点论述了HD-Zip III在胚胎形态发生、顶端分生组织形成、叶极性建立和维管组织分化等发育过程中的作用, 系统总结了HD-Zip III基因在不同层次受到的调控, 探讨了该家族基因与陆生维管植物进化的关系。     

小黑杨HD-Zip转录因子家族生物信息学及应答盐胁迫分析

HD-Zip转录因子基因是植物中特有的一类蛋白家族,在植物生长发育和逆境应答胁迫过程中发挥重要作用。HD-Zip转录因子基因是由高度保守的同源异型结构域（HD）和亮氨酸拉链域（LZ）结构域构成的特殊结构模型。杨树HD-Zip转录因子家族共有63个基因,可被分为HD-ZipⅠ、HD-ZipⅡ、HD-ZipⅢ和HD-ZipⅣ四个亚家族。本文利用RNA-Seq分析了盐胁迫条件下HD-Zip基因家族在小黑杨根、茎、叶等不同组织的基因表达差异,从转录组水平揭示其应答胁迫环境的分子机制,结果表明,盐胁迫下在叶中有25个HD-Zip基因下调表达,21个基因上调表达;茎中有42个基因下调表达,11个基因上调表达;根中有26个基因下调表达,24个基因上调表达。另外,本文根据拟南芥HD-Zip转录因子家族基因的已知功能,预测了杨树HD-Zip转录因子同源基因的功能,并利用生物信息学方法分析了杨树HD-Zip转录因子蛋白序列的保守结构域、氨基酸组成和理化性质等,为进一步研究杨树HD-Zip转录因子基因功能提供参考。     

Roles for Class III HD-Zip and KANADI genes in Arabidopsis root development

Meristems within the plant body differ in their structure and the patterns and identities of organs they produce. Despite these differences, it is becoming apparent that shoot and root apical and vascular meristems share significant gene expression patterns. Class III HD-Zip genes are required for the formation of a functional shoot apical meristem. In addition, Class III HD-Zip and KANADI genes function in patterning lateral organs and vascular bundles produced from the shoot apical and vascular meristems, respectively. We utilize both gain- and loss-of-function mutants and gene expression patterns to analyze the function of Class III HD-Zip and KANADI genes in Arabidopsis roots. Here we show that both Class III HD-Zip and KANADI genes play roles in the ontogeny of lateral roots and suggest that Class III HD-Zip gene activity is required for meristematic activity in the pericycle analogous to its requirement in the shoot apical meristem.     

白桦HD-Zip基因家族生物信息学及应答盐胁迫分析

HD-Zip转录因子蛋白家族是植物特有的一类转录因子蛋白,在植物生长发育和抵抗逆境胁迫等过程中发挥着重要作用。利用白桦全基因组数据库,获得白桦35条HD-Zip蛋白序列,参考拟南芥中该家族的分类方法,将这些成员分成HD-ZipⅠ-Ⅳ四个亚家族,并对这些成员的蛋白保守结构域、氨基酸组成、染色体分布、和理化性质等进行了预测和分析。从高盐处理的白桦幼苗根组织的转录组数据,鉴定了7个差异表达的基因。本研究为进一步研究白桦HD-Zip家族基因调控白桦耐盐性的功能提供了理论支持。     

植物HD-Zip转录因子的生物学功能

HD-Zip转录因子属于Homeobox蛋白家族, 是植物特异转录因子, 由高度保守的HD(Homeodomain)结构域和Leu zipper(Zip)元件组成, 前者与DNA特异结合, 后者介导蛋白二聚体的形成。HD-Zip转录因子家族包括4个亚家族(HD-Zip Ⅰ-Ⅳ), 其成员通过与其他蛋白互作、参与激素介导的信号途径, 从而调控植物生长发育、光形态建成、花发育、果实发育和植物对逆境应答等生物学过程。文章对近几年关于植物HD-Zip转录因子参与上述生物学功能方面的研究进行了综述, 以期对新功能基因的挖掘和应用研究以及HD-Zip调控机制的阐明奠定基础。     

The Arabidopsis Athb-8, -9 and genes are members of a small gene family coding for highly related HD-ZIP proteins

We report the isolation and characterization of two Arabidopsis homeobox genes highly related to the Athb-8 gene. The full-length cDNAs encode proteins of 841 and 852 amino acids which we have designated Athb-9 and -14, respectively. Athb-8, -9 and -14 are members of a small family of HD-Zip proteins (HD-ZIP III) characterized by a HD-Zip motif confined to the N-terminus of the polypeptide. The spatial organization of the HD-Zip domain of Athb-8, -9 and -14 is different from that of the Athb-1 (a member of the HD-ZIP I family) and Athb-2 (a member of the HD-ZIP II family) HD-Zip domains. DNA binding analysis performed with random-sequence DNA templates showed that the Athb-9 HD-Zip (HD-Zip-9) domain, but not the Athb-9 HD alone, binds to DNA. The HD-Zip-9 domain recognizes a 11 bp pseudopalindromic sequence (GTAAT(G/C)ATTAC), as determined by selecting high-affinity binding sites from random-sequence DNA. Moreover, gel retardation assays demonstrated that the HD-Zip-9 domain binds to DNA as a dimer. These data support the notion that the HD-ZIP III domain interacts with DNA recognition elements in a fashion similar to the HD-ZIP I and II domains.