Prasad C Krishna, Meyers Craig, Zhan De-Jin, You Hong, Chiriva-Internati Maurizio, Mehta Jawahar L, Liu Yong, Hermonat Paul L
Department of Internal Medicine, Gene Therapy Center for Molecular Medicine, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
Virology. 2003 Sep 15;314(1):423-31. doi: 10.1016/s0042-6822(03)00439-2.
Multiple epidemiologic studies show that adeno-associated virus (AAV) is negatively associated with cervical cancer (CX CA), a cancer which is positively associated with human papillomavirus (HPV) infection. Mechanisms for this correlation may be by Rep78's (AAV's major regulatory protein) ability to bind the HPV-16 p97 promoter DNA and inhibit transcription, to bind and interfere with the functions of the E7 oncoprotein of HPV-16, and to bind a variety of HPV-important cellular transcription factors such as Sp1 and TBP. c-Jun is another important cellular factor intimately linked to the HPV life cycle, as well as keratinocyte differentiation and skin development. Skin is the natural host tissue for both HPV and AAV. In this article it is demonstrated that Rep78 directly interacts with c-Jun, both in vitro and in vivo, as analyzed by Western blot, yeast two-hybrid cDNA, and electrophoretic mobility shift-supershift assay (EMSA supershift). Addition of anti-Rep78 antibodies inhibited the EMSA supershift. Investigating the biological implications of this interaction, Rep78 inhibited the c-Jun-dependent c-jun promoter in transient and stable chloramphenicol acetyl-transferase (CAT) assays. Rep78 also inhibited c-Jun-augmented c-jun promoter as well as the HPV-16 p97 promoter activity (also c-Jun regulated) in in vitro transcription assays in T47D nuclear extracts. Finally, the Rep78-c-Jun interaction mapped to the amino-half of Rep78. The ability of Rep78 to interact with c-Jun and down-regulate AP-1-dependent transcription suggests one more mechanism by which AAV may modulate the HPV life cycle and the carcinogenesis process.
多项流行病学研究表明，腺相关病毒（AAV）与宫颈癌（CX CA）呈负相关，而宫颈癌与人乳头瘤病毒（HPV）感染呈正相关。这种相关性的机制可能是Rep78（AAV的主要调节蛋白）能够结合HPV - 16 p97启动子DNA并抑制转录，结合并干扰HPV - 16 E7癌蛋白的功能，以及结合多种对HPV重要的细胞转录因子，如Sp1和TBP。c - Jun是另一个与HPV生命周期以及角质形成细胞分化和皮肤发育密切相关的重要细胞因子。皮肤是HPV和AAV的天然宿主组织。本文通过蛋白质免疫印迹法、酵母双杂交cDNA和电泳迁移率变动-超迁移分析（EMSA超迁移）分析表明，Rep78在体外和体内均能直接与c - Jun相互作用。添加抗Rep78抗体可抑制EMSA超迁移。在瞬时和稳定的氯霉素乙酰转移酶（CAT）分析中研究这种相互作用的生物学意义时，Rep78抑制了c - Jun依赖的c - jun启动子。在T47D核提取物的体外转录分析中，Rep78还抑制了c - Jun增强的c - jun启动子以及HPV - 16 p97启动子活性（也是由c - Jun调节的）。最后，Rep78与c - Jun的相互作用定位于Rep78的氨基端。Rep78与c - Jun相互作用并下调AP - 1依赖转录的能力表明，AAV可能通过另一种机制调节HPV生命周期和致癌过程。
