HPV基因的进化分析

目的:HPV有许多类型,其大致可分为高危型和低危型,高危型HPV感染是导致宫颈癌发生的首要原因,在HPV基因组中,E6基因是促进宫颈细胞癌变的关键基因,本文主要研究HPV中的E6基因在各种不同型别的HPV中的进化关系,并对E2基因碱基替换率进行分析,探讨高危型HPV与低危型HPV的区别.方法:本文对不同类型HPV E6氨基酸序列构建系统发生树,探讨识别高危型HPV可能的一致序列,对E6基因其中一处能导致恶性程度增加的突变进行分析.并对HPV16与其位于同一颗树的HPV35和HPV31计算相对碱基替换率.结果:高危型HPV均源自同一株病毒株的进化.各种HPV型别中,高危型HPV E6蛋白对应于HPV16E6蛋白的第83位氨基酸为缬氨酸更为保守,HPV中除E2以外的其他基因的非同义替换率均小于同义替换率.结论:HPV E6蛋白对应于HPV16E6蛋白的第83位氨基酸为缬氨酸能更好地实现HPV E6蛋白的致癌作用.HPV基因中除E2以外的基因在进化过程中都较为保守,是HPV增殖生长的关键基因,而E2部分区域非同义替换率大于同义替换率,说明E2这部分区域的突变能够更好的促进HPV的增殖和生长.

Analysis on the Evolution of HPV Gene

Objective： HPV gene has many types.They can be roughly divided into two types,one is the high risk HPV gene type and the other is the low risk HPV gene type.Infection of the high risk HPV gene type is the primary cause that lead to the cervical carcinoma.This article mainly researches the evolutionary relationship of E6 gene in different HPV types.Analyzes the nucleotide substitutions rate.Discusses the differences between the high risk HPV gene and the low risk HPV gene.Methods： In this article,phylogenetic tree is constructed for different types of HPV gene＇s amino acid sequence,possible consistent sequence that are useful for high risk HPV gene＇s identification also be discussed and analyzed a genetic mutation of E6 gene that can cause malignancy increased.Then calculated the relative nucleotide substitutions of HPV16,HPV35 and HPV31 because they are on the same tree.Results： High risk HPV originate from the same viral strain.The valine which is the 83th amino acid of HPV16 E6 protein is more conserved.Except for E2 gene,other genes nonsynonymous substitution rate are less than synonymous substitution rate in HPV.Conclusions： Mutation can enhance carcinogenesis of HPVE6 protein when site corresponds to 83th amino acid of HPV16E6 protein is Valine.All of the genes of HPV are conserved in the evolution except E2.Therefore E2 gene is the important gene for proliferation of HPV.And nonsynonymous substitution rate of E2 gene in some areas is greater than synonymous substitution rate.Which means mutation of these areas can preferably promote the growth and proliferation of HPV.