Byrd P J, Grand R J, Breiding D, Williams J F, Gallimore P H
Department of Cancer Studies, University of Birmingham, Medical School, United Kingdom.
Virology. 1988 Mar;163(1):155-65. doi: 10.1016/0042-6822(88)90242-5.
The human adenovirus type 12 (H12) E1A region encodes two early proteins of 266 amino acid residues (266R) and 235R whilst the H12 E1B promoter directs the synthesis of two major proteins of 163R and 482R. To determine the functions of E1A and E1B in lytic infection and oncogenic transformation we have isolated and characterized a series of H12 E1 mutants. Mutant H12 hr 700 contains a point mutation in exon 1 that alters a single amino acid common to both the 266 and 235R proteins. This mutant synthesized reduced levels of E1 and structural proteins at delayed times in HEK cells, transformed BRK cells, and induced tumors in newborn rats at reduced efficiency compared to wild-type virus. The mutation in H12 in 600 truncates the 266R protein in its unique sequences but this mutant synthesized the 235R, E1B, and structural proteins at delayed times in HEK cells. H12 in 600 was nontransforming but induced rare tumors in newborn rats. A third E1A mutant H12 in 601 synthesized no E1A proteins, reduced levels of E1B and structural proteins at delayed times in lytic infections, and was not a transforming or oncogenic virus. Three E1B mutants were studied in detail. Both H12 hr 703 and H12 in 602 encode N-terminal truncated 482R proteins whereas H12 del 620 encodes an in-frame internally deleted 482R protein. All three synthesized reduced amounts of E1A proteins and the E1B 163R protein, identifying a regulatory function for the 482R protein. None of the E1B mutants could transform and only H12 del 620 could induce rare tumors in newborn rats. These results show that H12 oncogenesis requires the coordinated expression of the E1 proteins.
人12型腺病毒（H12）的E1A区域编码两种分别含266个氨基酸残基（266R）和235个氨基酸残基（235R）的早期蛋白，而H12的E1B启动子指导合成两种主要蛋白，分别含163个氨基酸残基（163R）和482个氨基酸残基（482R）。为了确定E1A和E1B在裂解感染和致癌转化中的功能，我们分离并鉴定了一系列H12 E1突变体。突变体H12 hr 700在外显子1中存在一个点突变，该突变改变了266R和235R蛋白共有的一个氨基酸。与野生型病毒相比，该突变体在HEK细胞中延迟合成E1和结构蛋白的水平降低，可转化BRK细胞，但在新生大鼠中诱导肿瘤的效率降低。H12 in 600中的突变在其独特序列中截短了266R蛋白，但该突变体在HEK细胞中延迟合成235R、E1B和结构蛋白。H12 in 600无转化能力，但在新生大鼠中诱导罕见肿瘤。第三个E1A突变体H12 in 601不合成E1A蛋白，在裂解感染中延迟合成E1B和结构蛋白的水平降低，且不是转化病毒或致癌病毒。对三个E1B突变体进行了详细研究。H12 hr 703和H12 in 602均编码N端截短的482R蛋白，而H12 del 620编码框内内部缺失的482R蛋白。这三个突变体均合成减少量的E1A蛋白和E1B 163R蛋白，表明482R蛋白具有调节功能。没有一个E1B突变体能够转化，只有H12 del 620能够在新生大鼠中诱导罕见肿瘤。这些结果表明，H12致癌作用需要E1蛋白的协调表达。
