Role of HPV16 E7/E2F6 interaction in viral oncogenesis

描述（由申请人提供）：高危人乳头瘤病毒（HPV），包括HPV 16，几乎存在于所有宫颈癌中。HPV诱导的癌变是HPV E6和E7表达失调的结果。由于HPV基因组复制和病毒体产生发生在上皮的最分化层中，因此E6和E7破坏分化期间信号生长停滞的途径;例如，高危HPV E6和E7分别损害p53和pRB肿瘤抑制因子。初步证据表明，HPV 16 E7癌蛋白可与E2 F6相互作用，E2 F6是细胞周期调控基因转录的特异性阻遏物。该建议旨在通过免疫共沉淀、突变体定位和报告基因测定来表征相互作用。将使用北方和ChIP分析确定E2 F6介导的E7抑制的变化。该提议的中心假设是E7解除E2 F6介导的转录抑制，从而提供另一层控制，通过该控制，HPV确保感染的宿主细胞保持S期能力，这对于病毒基因组复制至关重要，并可能有助于细胞转化。这些研究将进一步了解病毒蛋白如何与细胞因子相互作用以诱导癌症。

DESCRIPTION (provided by applicant): High-risk human papillomaviruses (HPVs), including HPV16, are present in nearly all cervical carcinomas. HPV-induced carcinogenesis is a result of the dysregulated expression of HPV E6 and E7. Because HPV genome replication and virion production occur in the most differentiated layers of the epithelium, E6 and E7 subvert pathways that signal growth arrest during differentiation; for instance, high-risk HPV E6 and E7 compromise the p53 and pRB tumor suppressors, respectively. Preliminary evidence shows that the HPV16 E7 oncoprotein can interact with E2F6, a specific repressor of transcription of cell cycle regulated genes. This proposal aims to characterize the interaction by co-immunoprecipitations, mutant mapping, and reporter assays. Changes in E2F6-mediated repression by E7 will be determined using Northern and ChIP analyses. The central hypothesis of this proposal is that E7 relieves E2F6-mediated transcriptional repression, thus providing yet another layer of control by which HPV ensures that the infected host cell remains S-phase competent, which is vital for viral genome replication and likely contributes to cellular transformation. These studies will further the understanding of how viral proteins interact with cellular factors to induce cancer.