Farr A, Pattison S, Youn B S, Roman A
Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis 46202-5120, USA.
J Gen Virol. 1995 Apr;76 ( Pt 4):827-35. doi: 10.1099/0022-1317-76-4-827.
Human papillomavirus type 6 (HPV-6) DNA is the predominant HPV type found in condyloma acuminata: it is rarely found in carcinomas. We have previously reported cloning and characterizing an HPV-6 from a vulvar condyloma (HPV6-W50) and an HPV-6 from a vulvar carcinoma (HPV6-T70). The E5, E6 and E7 proteins encoded by the two genomes were identical, however, the two genomes differed in the long control region (LCR). Cloning of the entire LCR into the enhancerless plasmid pSVEcat showed that the two LCRs had comparable enhancer activity. Since the major differences between the two LCRs resided in the 5' end of the LCR, upstream of the L1 polyadenylation signal, we subcloned the two LCRs to analyse more closely their effect on cat gene expression. The data indicated that LCR subclones of the two genomes had comparable chloramphenicol acetyltransferase (CAT) activity. A negative regulatory region was detectable when the test plasmids were transfected into HeLa and C33A cells and in primary keratinocytes. A decrease in CAT activity was also detected when the SV40 early promoter was replaced with the putative HPV-6 E6 promoter. The negative regulatory region functioned in a position- and orientation-independent manner, thus fulfilling the definition of a silencer.
人乳头瘤病毒6型（HPV-6）DNA是尖锐湿 疣中发现的主要HPV类型：在癌组织中很少发现。我们之前报道过从一例外阴尖锐湿 疣（HPV6-W50）和一例外阴癌（HPV6-T70）中克隆并鉴定HPV-6。两个基因组编码的E5、E6和E7蛋白是相同的，然而，两个基因组在长控制区（LCR）存在差异。将整个LCR克隆到无增强子的质粒pSVEcat中，结果显示两个LCR具有相当的增强子活性。由于两个LCR的主要差异位于LCR的5'端，即L1多聚腺苷酸化信号的上游，我们对两个LCR进行亚克隆，以更仔细地分析它们对cat基因表达的影响。数据表明，两个基因组的LCR亚克隆具有相当的氯霉素乙酰转移酶（CAT）活性。当将测试质粒转染到HeLa和C33A细胞以及原代角质形成细胞中时，可检测到一个负调控区。当用推定的HPV-6 E6启动子取代SV40早期启动子时，也检测到CAT活性降低。负调控区以位置和方向独立的方式发挥作用，因此符合沉默子的定义。
