Johnsen C K, Stanley M, Norrild B
Protein Laboratory, Panum Institute, Copenhagen, Denmark.
Intervirology. 1995;38(6):339-45. doi: 10.1159/000150461.
During a human papillomavirus infection (HPV), a set of spliced messenger RNAs (mRNA) are produced from the coding strand of the 8-kilobase virus DNA genome. These mRNAs have been isolated from cervical intraepithelial neoplasia biopsies, tumor biopsies and HPV type 16 (HPV-16)-containing cell lines, and subsequent analyses have shown that the different mRNAs are obtained by often complex splicing events. In the present study we have investigated the coding capacity of the HPV-16 E5 open reading frame (ORF) in an in vitro translation system and by the expression of a HPV-16 E5-CAT fusion gene from bicistronic messenger RNAs derived from polycistronic mRNAs which have previously been identified by others. Our results show that the HPV-16 E5 protein synthesis can only be initiated from the authentic ATG codon in the presence of E2 ORF translation. The E5 gene is found to be expressed only from a bicistronic mRNA with an E2 ORF upstream of the E5 gene indicating that the E5 protein is synthesized coordinated with the E2 protein. The supposition that the E5 protein is synthesized early in infection is discussed.
在人乳头瘤病毒（HPV）感染期间，一组剪接的信使核糖核酸（mRNA）由8千碱基病毒DNA基因组的编码链产生。这些mRNA已从宫颈上皮内瘤变活检组织、肿瘤活检组织以及含16型人乳头瘤病毒（HPV - 16）的细胞系中分离出来，随后的分析表明，不同的mRNA是通过通常复杂的剪接事件获得的。在本研究中，我们通过体外翻译系统以及表达来自双顺反子信使核糖核酸的HPV - 16 E5 - CAT融合基因，研究了HPV - 16 E5开放阅读框（ORF）的编码能力，这些双顺反子信使核糖核酸来源于先前已被其他人鉴定的多顺反子mRNA。我们的结果表明，HPV - 16 E5蛋白合成仅在E2 ORF翻译存在的情况下才能从真实的ATG密码子起始。发现E5基因仅从E5基因上游带有E2 ORF的双顺反子mRNA表达，这表明E5蛋白与E2蛋白协同合成。文中讨论了E5蛋白在感染早期合成的假设。
