烟草C2H2锌指蛋白转录因子家族成员的鉴定与表达分析

C2H2锌指蛋白转录因子家族在真核生物中具有重要的生物学功能,广泛参与植物叶的发生、花器官的调控、侧枝的形成及逆境胁迫等生命过程。植物C2H2锌指蛋白不仅结合DNA和RNA,而且与蛋白质之间相互作用。本研究利用普通烟草(Nicotiana tabacum)基因组数据库,运用Blastp比对,结合Pfam和SMART分析,鉴定了118条普通烟草C2H2锌指蛋白家族成员;对烟草C2H2锌指蛋白家族进行了进化树分析、结构域分析、物理化学性质分析、染色体定位、基因结构分析、三维结构分析及组织表达分析等。结果表明：不同成员的氨基酸长度差异较大;系统进化及结构域分析显示,所有C2H2家族成员可以被分为5个亚家族,同一亚家族成员之间在结构域和理化性质上呈现较高一致性;每个成员都含有C2H2结构域,在数量上存在较大差异;将所有基因家族成员定位在22条染色体上;组织表达分析表明,每个C2H2亚家族都有成员在不同组织中表达,在叶及根中有些基因的表达量较高。     

C2H2型锌指蛋白的研究进展

锌指基因家族是人体中最大的基因家族,它参与细胞分化、胚胎发育,并与许多疾病的发生相关．根据半胱氨酸(c)和组氨酸(H)的数目和位置可将锌指蛋白分为c2H2、c2Hc2、c2c2 CHCC2C2、C2C2C2C2等亚类．c2H2型锌指是最普遍的类型,它们作为重要的转录调控因子参与许多的生理过程．c2H2型锌指蛋白包含的锌指数目从1个到30多个不等．依据锌指的数量以及在蛋白中的分布情况,大多数c2H2型锌指蛋白属于下列3类之一：1)含3个c：H：锌指的蛋白(tC2H2);2)含多个锌指的c2H2型锌指结构蛋白(mac2H2);3)锌指成对间隔排列的c2H2型锌指蛋白(spC2H2)、一些c2H2型锌指蛋白能识别并结合特异性RNA或DNA片段．另一些则只能与RNA结合．通常锌指蛋白含锌指数目越多。它选择结合的能力就越强．     

大豆C2H2型锌指蛋白基因SCTF-1的克隆及功能分析

锌指蛋白是一类具有手指型结构的蛋白质,其中一些锌指蛋白是转录因子,对真核生物的生长发育及非生物逆境胁迫的耐受能力都有着重要作用。文章从大豆(Glycine max(L.)Merr.)中克隆了一个新的C2H2型锌指蛋白基因SCTF-1(GenBank登录号:JQ692081),该基因包含一个699 bp的开放阅读框,编码233个氨基酸,无内含子,有两个典型的C2H2型锌指结构。锌指结构中有植物锌指蛋白特有的保守氨基酸序列QALGGH。经软件预测分析,其等电点pI=8.33,分子量24.9 kDa。农杆菌介导的洋葱表皮细胞GFP瞬时表达实验结果表明,SCTF-1蛋白能够定位到细胞核中。通过RT-PCR检测发现该基因在大豆叶和花中的表达量较高,在茎和根的表达量相对较低。在对大豆幼苗的低温胁迫中,SCTF-1基因的表达量明显增加。将SCTF-1基因转入烟草(Nicotiana tabacum L.)中,发现SCTF-1基因的过量表达能够明显提高转基因烟草的耐冷能力。     

Expression analysis of an Arabidopsis C2H2 zinc finger protein gene

C₂H₂ zinc finger protein genes encode nucleic acid-binding proteins involved in the regulation of gene activity. AtZFP1 (Arabidopsis thaliana zinc finger protein 1) is one member of a small family of C₂H₂ zinc finger-encoding sequences previously characterized from Arabidopsis. The genomic sequence corresponding to the AtZFP1 cDNA has been determined. Molecular analysis demonstrates that AtZFP1 is a unique, intronless gene which encodes a 1100 nucleotides mRNA highly expressed in roots and stems. A construct in which 2.5 kb of AtZFP1 upstream sequences is linked to the -glucuronidase gene was introduced into Arabidopsis by Agrobacterium-mediated transformation of roots. Histochemical analysis of transgenic Arabidopsis carrying the AtZFP1 promotor:-glucuronidase fusion shows good correlation with RNA blot hybridization analysis. This transgenic line will be a useful tool for analyzing the regulation of AtZFP1 to further our understanding of its function.     

Solution structure of the C4 zinc finger domain of HDM2

HDM2 is a ubiquitin E3 ligase that is a key negative regulator of the tumor suppressor p53. Here, we report the determination of the solution structure of the C4 zinc finger domain of HDM2 using multidimensional NMR. The HDM2 C4 zinc finger domain has a fold consisting of a 3(10) helix followed by four beta-strands, which shares significant structural similarity to the zinc ribbon protein family. Family based sequence analysis identified two putative binding sites, one of which resembles an RNA binding motif.     

The CCCH-type zinc finger proteins AtSZF1 and AtSZF2 regulate salt stress responses in Arabidopsis

The molecular mechanism governing the response of plants to salinity stress, one of the most significant limiting factors for agriculture worldwide, has just started to be revealed. Here, we report AtSZF1 and AtSZF2, two closely related CCCH-type zinc finger proteins, involved in salt stress responses in Arabidopsis. The expression of AtSZF1 and AtSZF2 is quickly and transiently induced by NaCl treatment. Mutants disrupted in the expression of AtSZF1 or AtSZF2 exhibit increased expression of a group of salt stress-responsive genes in response to high salt. Significantly, the atszf1-1/atszf2-1 double mutant displays more sensitive responses to salt stress than the atszf1-1 or atszf2-1 single mutants and wild-type plants. On the other hand, transgenic plants overexpressing AtSZF1 show reduced induction of salt stress-responsive genes and are more tolerant to salt stress. We also showed that AtSZF1 is localized in the nucleus. Taken together, these results demonstrated that AtSZF1 and AtSZF2 negatively regulate the expression of salt-responsive genes and play important roles in modulating the tolerance of Arabidopsis plants to salt stress.     

水稻C2H2型锌指蛋白基因RZF71的克隆与表达分析

利用生物信息学和RT-PCR方法从水稻幼苗组织中分离了1个新的C2H2型锌指蛋白基因RZF71, 该基因编码一条250个氨基酸残基的多肽, 含有两个典型的C2H2型锌指结构。半定量RT-PCR分析表明: RZF71在根、茎、叶和幼穗中呈组成性表达, 在根中的表达丰度略高; 在高盐和PEG6000胁迫的水稻幼苗组织中, RZF71的表达显著增强, 但低温和ABA处理对该基因的表达量影响不大。农杆菌介导的洋葱表皮细胞GFP瞬时表达实验表明: RZF71定位于细胞核内。讨论了RZF71可能作为一个转录调控因子在水稻耐高盐和渗透胁迫中的作用。     

17个新的C2H2型锌指基因片段的分离与克隆

按照Ｃ２Ｈ２型锌指基因保守结构域的ＤＮＡ序列设计一对简并引物,以人基因组ＤＮＡ为模板进行ＰＣＲ同源扩增,将由此获得的锌指基因片段为探针,从人胎肾、骨骼肌、骨骼组织的ｃＤＮＡ分子库中筛选到２２个Ｃ２Ｈ２型锌指蛋白ｃＤＮＡ片段,经国际ＮＣＢＩ数据库查询检索,其中１７个为新的锌指基因片段。对从胎肾ｃＤＮＡ分子库中分离到的Ｋ３－４和Ｋ５－１２克隆进行了表达谱分析,发现Ｋ３－４在肾脏中的表达量明显高于其他几     

A multiscale approach to simulating the conformational properties of unbound multi‐C2H2 zinc finger proteins

The conformational properties of unbound multi‐Cys₂His₂ (mC₂H₂) zinc finger proteins, in which zinc finger domains are connected by flexible linkers, are studied by a multiscale approach. Three methods on different length scales are utilized. First, atomic detail molecular dynamics simulations of one zinc finger and its adjacent flexible linker confirmed that the zinc finger is more rigid than the flexible linker. Second, the end‐to‐end distance distributions of mC₂H₂ zinc finger proteins are computed using an efficient atomistic pivoting algorithm, which only takes excluded volume interactions into consideration. The end‐to‐end distance distribution gradually changes its profile, from left‐tailed to right‐tailed, as the number of zinc fingers increases. This is explained by using a worm‐like chain model. For proteins of a few zinc fingers, an effective bending constraint favors an extended conformation. Only for proteins containing more than nine zinc fingers, is a somewhat compacted conformation preferred. Third, a mesoscale model is modified to study both the local and the global conformational properties of multi‐C₂H₂ zinc finger proteins. Simulations of the CCCTC‐binding factor (CTCF), an important mC₂H₂ zinc finger protein for genome spatial organization, are presented. Proteins 2015; 83:1604–1615. © 2015 Wiley Periodicals, Inc.