Phenotypic determinants of adenovirus E1A gene autoregulation: variable region between conserved coding domains 2 and 3.
Phenotypic determinants of adenovirus E1A gene autoregulation: variable region between conserved coding domains 2 and 3.
复制标题
腺病毒E1A基因自动调节的表型决定因素：保守编码域2和3之间的可变区。
DOI：
10.1006/viro.1995.0039
复制
发表时间：
1995
期刊：
影响因子：
--
通讯作者：
Tibbetts,C
中科院分区：
文献类型：
--
作者：
Hamid,R;Cogan,JD;Jones,SN;Tibbetts,C
人腺病毒的不同血清型和进化变体表现出病毒E1A基因的正性和负性自动调节的独特模式。3型腺病毒（Ad3）E1A基因的E1A启动子自动调节突变使Ad3hr15不能在正常允许的细胞中生长。该启动子突变在异源5型辅助腺病毒（Ad5）的E1A产物中是互补的。Ad3hr15的第二位点回复突变体恢复了高水平E1A基因表达的活力。回复突变体E1A基因型保留突变体E1A启动子，并在阻遏和激活相关保守结构域CR2和CR3之间的非保守区域中具有小的框内缺失。质粒表达载体构建为回复突变体E1A基因的12S和13S cDNA形式。这些被用于与突变体Ad3hr15 E1A启动子的转录控制下的报告基因质粒的共转染实验。辅助Ad5或回复突变体12S E1A cDNA对Ad3hr15 E1A启动子的抑制始终大于野生型Ad3 12S E1A cDNA表达的抑制。与突变体编码的野生型Ad3 13S E1A cDNA相比，在与Ad5的13S cDNA或Ad3hr15回复体的13S E1A cDNA共转染中观察到显著更高水平的正反式激活。Ad3hr15的Ad5辅助型和dl回复突变型与共表达的E1A基因的反式激活活性有关。将3型E1A基因的保守编码区CR2和CR3分开的非保守区起到减弱E1A介导的转录抑制和反式激活的作用。
Different serotypes and evolutionary variants of human adenoviruses exhibit distinctive patterns of positive and negative autoregulation of the viral E1A gene. An autoregulatory E1A promoter mutation of the adenovirus type 3 (Ad3) E1A gene renders Ad3hr15 incapable of growth in normally permissive cells. The promoter mutation is complementedin transby E1A products of the heterologous helper adenovirus type 5 (Ad5). Second-site revertants of Ad3hr15 restore viability with high levels of E1A gene expression. The revertant E1A genotypes retain the mutant E1A promoter and have small in-frame deletions in the nonconserved region between the repression- and activation-associated conserved domains CR2 and CR3. Plasmid expression vectors were constructed as 12S and 13S cDNA forms of revertant E1A genes. These were used in cotransfection experiments with a reporter gene plasmid under transcriptional control of the mutant Ad3hr15 E1A promoter. The repression of the Ad3hr15 E1A promoter by helper Ad5 or revertant 12S E1A cDNA was consistently greater than that effected by wild-type Ad3 12S E1A cDNA expression. Significantly greater levels of positive transactivation were observed in cotransfections with 13S cDNAs of Ad5 or with the 13S E1A cDNA of Ad3hr15 revertants, compared to the transactivation observed with the mutant-encoded wild-type Ad3 13S E1A cDNA. The Ad5 helper anddl-revertant phenotype of Ad3hr15 appear to be related to transactivation activities of coexpressed E1A genes. The nonconserved region which separates the conserved coding regions CR2 and CR3 of the type 3 E1A gene acts to attenuate E1A-mediated repression and transactivation of transcription.