Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành y học dành cho các bạn tham khảo đề tài: Viral trans-factor independent replication of human papillomavirus genomes | Pittayakhajonwut and Angeletti Virology Journal 2010 7 123 http content 7 1 123 VIROLOGY JOURNAL RESEARCH Open Access Viral trans-factor independent replication of human papillomavirus genomes Daraporn Pittayakhajonwut and Peter C Angeletti Abstract Background Papillomaviruses PVs establish a persistent infection in the proliferating basal cells of the epithelium. The viral genome is replicated and maintained as a low-copy nuclear plasmid in basal keratinocytes. Bovine and human papillomaviruses BPV and HPV are known to utilize two viral proteins E1 a DNA helicase and E2 a transcription factor which have been considered essential for viral DNA replication. However growing evidence suggests that E1 and E2 are not entirely essential for stable replication of HPV. Results Here we report that multiple HPV16 mutants lacking either or both E1 and E2 open reading frame ORFs and the long control region LCR still support extrachromosomal replication. Our data clearly indicate that HPV16 has a mode of replication independent of viral trans-factors E1 and E2 which is achieved by origin activity located outside of the LCR. Background Papillomaviruses PVs infect the basal layers of epithelial cells and maintain their genomes at constant but relatively low-copy number in basal epithelial cells. These viruses replicate their genomes as nuclear plasmids in their natural mammalian host cells. Understanding of Human papillomavirus HPV replication has lagged behind that of other DNA viruses due to the need for development of efficient cell culture systems 1-3 . Most of our knowledge of HPV replication is derived from extensive studies of BPV1 in established rodent cell lines C127 since BPV1 was found to transform and replicate episomally in these cells. Short-term replication assays were performed in transformed cells in order to identify the cis- and fraws-elements that were required for replication of PVs 4 . Using this approach with BPV1 the early proteins E1 and
