百脉根LjCYCl基因克隆及其蛋白核定位

通过筛选百脉根(Lotus japonicus)基因组文库,克隆了LjCYCl(Lotus japonicus Cvcloidea-likel基因。LjCYCl是金鱼草(Antirrhium)CYC(Cycloidea)基因的同源基因,CYC属于TCP[TBl(teosinte branched 1),CYC,PCFs(PCF1 and PCF2)]基因家族,编码转录调控子控制金鱼草花的对称性。基因组序列分析表明,LjCYCl的开放阅读框(ORF)由两个外显子和一个内含子组成,其cDNA编码的LjCYCl蛋白包含了370个氨基酸。蛋白序列分析显示,LjCYCl包含一个TCP结构域和一个R结构域,属于TCP结构域蛋白家族的CYC／TBl亚家族;LjCYCl氨基酸序列与CYC相比,一致性和相似性分别为39．0％和42．6％。不同长度的LjCYCl-cDNA与报告基因GUS融合后,通过粒子轰击(particle bombardment)方法在洋葱表皮细胞瞬时表达融合蛋白,观察到包含了TCP结构域的融合蛋白能够进行细胞核定位,提示LjCYCl可能作为转录因子行使功能;TCP结构域自身不能完成核定位过程,还需要结构域两侧旁邻氨基酸序列的协助。     

百脉根LjCYC1基因克隆及其蛋白核定位

通过筛选百脉根(Lotus 7aponicus)基因组文库,克隆了LjCYC1(Lotus japonicus Cycloidea-like1)基因.L7CYC1是金鱼草(Antirrhium)CYC (Cycloidea)基因的同源基因,CYC属于TCP[TBl(teosinte branchedl),CYC,PCFs(PCFl and PCF2)]基因家族,编码转录调控子控制金鱼草花的对称性.基因组序列分析表明,LjCYC1的开放阅读框(ORF)由两个外显子和一个内含子组成,其cDNA编码的LjCYC1蛋白包含了370个氨基酸.蛋白序列分析显示,LjCYC1包含一个TCP结构域和一个R结构域,属于TCP结构域蛋白家族的CYC/TBl亚家族;LjCYCl氨基酸序列与CYC相比,一致性和相似性分别为39.0%和42.6%.不同长度的LjCYCl-cDNA与报告基因GUS融合后,通过粒子轰击(particle bombardment)方法在洋葱表皮细胞瞬时表达融合蛋白,观察到包含了TCP结构域的融合蛋白能够进行细胞核定位,提示LjCYCl可能作为转录因子行使功能;TCP结构域自身不能完成核定位过程,还需要结构域两侧旁邻氨基酸序列的协助.     

In silico characterization of the INO80 subfamily of SWI2/SNF2 chromatin remodeling proteins

Proteins belonging to SNF2 family of DNA dependent ATPases are important members of the chromatin remodeling complexes that are implicated in epigenetic control of gene expression. The yeast Ino80, the catalytic ATPase subunit of the INO80 complex, is the most recently described member of the SNF2 family. Outside the conserved ATPase domain, it has very little similarity with other well-characterized SNF2 proteins hence it is believed to represent a new subfamily. We have identified new members of this subfamily in different organisms and have detected characteristic features of this subfamily. Using various data mining tools we have identified a new, previously undetected domain in all members of this subfamily. This domain designated DBINO is characteristic of the INO80 subfamily and is predicted to have DNA-binding function. The presence of this domain in all the INO80 subfamily proteins from different organisms suggests its conserved function in evolution.     

甘薯基因组 TCP转录因子鉴定与逆境胁迫表达分析

基于甘薯( Ipomoea batatas ( L.) Lam.)全基因组序列, 利用生物信息学方法鉴定筛选了全基因组中的TCP( teosinte branched1/cincinnata/proliferating cell factor)转录因子, 并分析了甘薯苗期在蔓割病菌胁迫及块根储藏期低温胁迫下TCP基因的...     

水稻OsTB1基因的结构及其表达分析

TCP基因是一类植物中新发现的、可能具有转录因子活性的基因家族,成员包括金鱼草的Cyclodiea (Cyc)、玉米的Teosinte Branched1 (TB1)以及水稻中的PCF1、PCF2等.玉米的TB1基因有维持玉米顶端优势的作用,与分蘖的发生密切相关;水稻和玉米同属禾本科,在发育的过程中都有分蘖的发生.通过筛选水稻的基因组文库,得到了水稻中的一个TB1同源基因Oryza sativa Teosinte Branched1 (OsTB1).该基因不含内含子,基因编码一个长度为388个氨基酸的蛋白,在氨基酸水平上与TB1的同源性为70%,含有保守的TCP区和R区,是属于TCP基因家族的一个成员.RT-PCR和mRNA原位杂交分析结果表明,OsTB1在水稻的侧芽中有很强的表达,在花序中有较弱的表达.以上结果显示该基因可能在水稻侧芽和花序的起始和发育过程中起重要作用.     

烟草TCP家族成员鉴定及表达分析

TCP家族作为植物特有的转录因子,在植物发育的不同方面发挥着重要作用。为筛选烟草中TCP家族成员,本研究通过全基因组同源比对,鉴定烟草与拟南芥TCP家族同源序列。利用生物信息学的方法分析其理化性质、系统进化关系、顺式作用元件等;筛选AtTCP3/AtTCP4的同源基因,并利用RT-qPCR检测在20% PEG6000处理下的基因表达量变化。结果表明烟草中含有TCP家族成员63个,其氨基酸序列长度范围为89−596 aa,蛋白亲水性(grand average of hydropathicity, GRAVY)范围为−1.147−0.125,等电点(isoelectric point, pI)范围为4.42−9.94,内含子个数为0−3,亚细胞定位均位于细胞核。保守结构域和系统进化关系分析结果表明,烟草TCP家族可分为PCF、CIN和CYC/TB1这3个亚家族且每个亚家族具有稳定序列。基因启动子区顺式作用元件结果表明,TCP家族基因含有低温顺式作用元件(LTR)及多种胁迫及代谢调控相关的元件(MYB、MYC)等顺式作用元件。基因表达模式分析表明,AtTCP3/AtTCP4同源基因(NtTCP6、NtTCP28、NtTCP30、NtTCP33、NtTCP42、NtTCP57和NtTCP63)在20% PEG6000处理下表达量显著上调表达/下调表达,并发现NtTCP30和NtTCP57基因对干旱胁迫响应较为明显。研究结果剖析了烟草基因组中的TCP家族,为烟草抗旱基因功能研究及品种培育提供了候选基因。     

Control of organ asymmetry in flowers of Antirrhinum

Organ asymmetry is thought to have evolved many times independently in plants. In Antirrhinum, asymmetry of the flower and its component organs requires cyc and dich gene activity. We show that, like cyc, the dich gene encodes a product belonging to the TCP family of DNA-binding proteins that is first expressed in the dorsal domain of early floral meristems. However, whereas cyc continues to be expressed throughout dorsal regions, expression of dich eventually becomes restricted to the most dorsal half of each dorsal petal. This correlates with the effects of dich mutations and ectopic cyc expression on petal shape, providing an indication that plant organ asymmetry can reflect subdomains of gene activity. Taken together, the results indicate that plant organ asymmetry can arise through a series of steps during which early asymmetry in the developing meristem is progressively built upon.     

Cloning and characterization of the CYC8 gene mediating glucose repression in yeast

Mutations in the CYC8 ( = SSN6) gene of Saccharomyces cerevisiae alleviate glucose repression of many glucose-repressible genes. The gene was isolated by screening for complementation of a cyc8 effect on colony morphology. Subclones containing a 5.3-kb SalI-XbaI fragment provided complete complementation. The gene was further localized to 3.5 kb by mapping of the CYC8 mRNA and insertional mutagenesis. Insertion and deletion mutations are viable and produce the same array of phenotypes as point mutations. CYC8 disruptions also had effects on the mating ability and morphology of MAT alpha cells similar to that of tup1 mutations. The nucleotide sequence of a 4866-bp fragment, including CYC8, was determined. One long open reading frame of 966 amino acid predicts a protein of molecular weight 10,7215. The predicted protein is extremely glutamine-rich, with blocks of 16 and 31 glutamines in tandem at the N and C regions, respectively. The CYC8 gene product lacks consensus sequences for DNA-binding domains, suggesting that its function may be different from classical repressor proteins.