Nelson C C, Braithwaite A W, Silvestro M, Bellett A J
Division of Cell Biology, John Curtin School of Medical Research, Australian National University, Canberra.
J Virol. 1990 Sep;64(9):4329-37. doi: 10.1128/JVI.64.9.4329-4337.1990.
Adenovirus infection was compared in F9 (OTF963) cells and cells induced to differentiate with retinoic acid, in order to study expression of early genes under the control of the reported "E1a-like factor" in F9 cells. However, not only was transcription of the viral E1a gene defective in undifferentiated cells but expression of all the other early genes was found to be reduced in OTF963 cells in comparison to differentiated cells. The defect in early gene expression was detected at the level of transcriptional initiation during the first 48 h of infection and resulted in similarly low levels of viral cytoplasmic mRNA and viral protein synthesis. Viral DNA replication was delayed and reduced. After 48 h of infection, the defect in transcription in OTF963 cells of E1a and other early genes was relieved, so that by 72 h postinfection the level of transcription was similar to that 16 h after infection of differentiated cells. At no time did adenovirus early gene expression occur independently of viral E1a. These results suggest limits to the generality and explanatory power of the hypothesis that F9 embryonal carcinoma cells contain an E1a-like factor.
为了研究F9（OTF963）细胞中在已报道的“E1a样因子”控制下早期基因的表达情况，对F9（OTF963）细胞和用视黄酸诱导分化的细胞中的腺病毒感染进行了比较。然而，不仅未分化细胞中病毒E1a基因的转录存在缺陷，而且与分化细胞相比，OTF963细胞中所有其他早期基因的表达也被发现有所降低。在感染的最初48小时内，早期基因表达的缺陷在转录起始水平被检测到，导致病毒细胞质mRNA和病毒蛋白合成水平同样较低。病毒DNA复制延迟且减少。感染48小时后，OTF963细胞中E1a和其他早期基因转录的缺陷得到缓解，因此到感染后72小时，转录水平与分化细胞感染16小时后的水平相似。腺病毒早期基因表达在任何时候都不会独立于病毒E1a发生。这些结果表明，F9胚胎癌细胞含有E1a样因子这一假说的普遍性和解释力存在局限性。
