作　　者： ; ; ; ; ; ; ; ; ;

机构地区： 西南大学

出　　处： 《蚕业科学》 2013年第2期302-309,共8页

摘　　要： 微孢子虫具有基因组进化速度慢,但基因进化速度快的特征,不同微孢子虫间存在较多的共线性区域。通过比较基因组分析在家蚕微孢子虫(Nosema bombycis,Nb)CQ1株中发现一个编号为NBO32g0035的功能未知新基因,而在兔脑炎微孢子虫(Encephalitozoon cuniculi)和蜜蜂微孢子虫(Nosema ceranae)均无该基因的存在。该基因编码521个氨基酸,其中有131个酸性氨基酸和76个碱性氨基酸,赖氨酸含量最高,半胱氨酸有6个,SignalP3.0预测该基因编码的蛋白质无信号肽。采用RT-PCR方法在被N.bombycis CQ1株感染1～10 d的家蚕中肠组织中能检测到该基因转录活性,并且仅能在家蚕微孢子虫基因组中获得其克隆序列。对该基因的克隆测序表明其核苷酸序列具有多态性。通过转染单细胞模式生物——酿酒酵母检测发现,该基因编码的蛋白质不具有明显的亚细胞定位特征,主要分布在酿酒酵母细胞的细胞质中。研究结果表明这个家蚕微孢子虫新基因具有在感染初期表达、核苷酸多态性的特点,其编码蛋白质定位于酿酒酵母细胞的细胞质中。 Microsporidian is typified by its high rate of gene evolution but low rate of genome evolution.There are many synteny blocks among different microsporidian species.Through comparative genomic analysis,we found a novel gene(numbered as NBO32g0035) with unknown function from Nosema bombycis CQ1 isolate.But no orthologous gene was found in genome of Encephalitozoon cuniculi and Nosema ceranae.This gene encodes 521 amino acids,among which 131 have acidic and 76 have basic side chains.The content of lysine is the highest.This protein has 6 cysteine residues and was predicted to have no peptide signal by SignalP3.0.RT-PCR results indicated that this gene was transcribed in silkworm midgut tissue on the 1st day to 10th day after infection by N.bombycis CQ1 isolate,and it could only be cloned from genome of N.bombycis.Nucleotide polymorphism on this gene was characterized by cloning and sequencing.After being transfected into Sacchromyces cerevisiae(a unicellular model organism),it was revealed that the protein encoded by this gene was not located in a specific region of the cell.Instead,it was mainly distributed in cytoplasm of S.cerevisiae cells.The obtained result showed that this novel N.bombycis gene had the characteristics of expression at early stage of infection and of nucleotide polymorphism,and its encoded protein was located in cytoplasm of S.cerevisiae cells.

关 键 词： 家蚕微孢子虫 共线性区域 基因 多态性 转录 细胞定位

领　　域： [生物学] [生物学]