Unidad de Investigación Biomédica en Cáncer, Instituto Nacional de Cancerología, México/Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México. Av. San Fernando No. 22, Col. Sección XVI, Tlalpan 14080, Mexico.
J Gen Virol. 2013 Feb;94(Pt 2):393-402. doi: 10.1099/vir.0.045807-0. Epub 2012 Oct 24.
A persistent infection with high-risk human papillomavirus (HPV) constitutes the main aetiological factor for cervical cancer development. HPV16 and 18 are the most prevalent types found in cervical cancer worldwide. It has been proposed that HPV intratype variations may result in differences in biological behaviour. Three different HPV18 variants belonging to the Asian Amerindian (AsAi), European (E) and African (Af) branches have been associated with specific histological types of cervical cancer with different relative prognoses, suggesting that HPV18 genomic variations might participate in disease evolution. The E1 viral protein plays a critical role in controlling viral replication and load, requiring interaction with the E2 protein to bind to the long control region (LCR). In this work, we analysed if intratype variations in the LCR and E1 and E2 genes of HPV18 impact ori replication. While the changes found in E2 genes of the tested variants were irrelevant in replication, we found that variations in E1 and LCR in fact affect ori function. It was demonstrated that nucleotide differences in the LCR variants impact ori function. Nevertheless, HPV18 E1 Af gene was mainly involved in the highest ori replication, compared with the E and AsAi E1 variants. Immunofluorescence analysis showed increased levels of Af E1 in the nucleus, correlating with the enhanced ori function. Site-directed mutagenesis revealed that at least two positions in the N-terminal domain of E1 could impact its nuclear accumulation.
高危型人乳头瘤病毒（HPV）的持续感染是宫颈癌发展的主要病因。HPV16 和 18 是全球宫颈癌中最常见的类型。有人提出，HPV 同种异型变异可能导致生物学行为的差异。三种不同的 HPV18 变体属于亚洲印第安人（AsAi）、欧洲（E）和非洲（Af）分支，与宫颈癌的特定组织学类型相关，具有不同的相对预后，这表明 HPV18 基因组变异可能参与疾病的演变。E1 病毒蛋白在控制病毒复制和载量方面起着关键作用，需要与 E2 蛋白相互作用才能结合到长控制区（LCR）。在这项工作中，我们分析了 HPV18 的 LCR 和 E1 和 E2 基因中的同种异型变异是否影响 ori 复制。虽然测试变体的 E2 基因中的变化对复制没有影响，但我们发现 E1 和 LCR 的变化实际上影响 ori 功能。事实证明，LCR 变体中的核苷酸差异影响 ori 功能。然而，与 E 和 AsAi E1 变体相比，HPV18 Af 基因的 E1 在 ori 复制中占主导地位。免疫荧光分析显示 Af E1 在核内的水平增加，与增强的 ori 功能相关。定点突变显示，E1 的 N 端结构域中的至少两个位置可能影响其核积累。
