两种微孢子虫全基因组中密码子偏好性比较  

Comparison of the Codon Bias Between Two Microsporidian Genomes

作　　者：张瑞芝[1,2] 向恒[1,3] 潘国庆[1] 李田[1] 周泽扬[1] 

机构地区：[1]西南大学蚕学与系统生物学研究所 [2]西南大学生物技术中心 [3]西南大学动物科技学院,重庆400715

出　　处：《蚕学通讯》2011年第1期1-8,共8页Newsletter of Sericultural Science

基　　金：中央高校基本科研业务费(No.XDJK2009C149);西南大学博士基金(No.SWU110047)

摘　　要：微孢子虫(Microsporidia)是一类细胞内营专性寄生的单细胞真核生物。基于其已测得的两个典型种的基因组数据,比较了家蚕微孢子虫(Nosema bombycis)与兔脑炎微孢子虫(Encephalitozoon cuniculi)之间全基因组的密码子偏好性异同。结果表明两基因组的密码子偏好性都较弱,基因表达程度都较低。而且二者之间确实存在显著差异,表现在兔脑炎微孢子虫的偏好性比家蚕微孢子虫的更弱,其最优密码子的偏好性也更弱,完全不同于家蚕微孢子虫偏向于使用第三位是A/U的最优密码子。这些差异与它们在核苷酸组成上的不同是一致的,有可能是两微孢子虫寄生于不同环境中导致了它们在密码子偏好性上的差异。Microsporidia are a group of obligate intracellular eukaryotic parasites.In this study,the codon bias was compared between Nosema bombycis and Encephalitozoon cuniculi based on their genomes.The results showed that the codon bias was rather weak in both genomes,indicating a low-level expression of their genes.Significant difference was observed between the two genomes in that the codon bias of E.cuniculi genome and of its optimal codons were weaker than those of N.bombycis.Most（93.10%） of the optimal codons in N.bombycis genome were found in the third bases with A/U,while 44.00% were noticed in E.cuniculi.The differences between the two genomes were shown to be consistent with their GC content（~30% for N.bombycis and ~47.6% for E.cuniculi）,and their different host environments might be a most important factor responsible for their different codon bias patterns.

关 键 词：微孢子虫 密码子偏好性 比较基因组学 

分 类 号：S884[农业科学—特种经济动物饲养]