Kwon B S, Weissman S M
J Virol. 1984 Dec;52(3):1000-4. doi: 10.1128/JVI.52.3.1000-1004.1984.
cDNA libraries from EL-4 cells treated with 12-O-tetradecanoyl phorbol-13-acetate (TPA) were screened for TPA-inducible sequences by differential hybridization. The most abundant inducible species was a sequence similar to that of mouse mammary tumor virus (MMTV). Induction of the mRNA corresponding to the MMTV-related sequences was already evident 30 min after TPA treatment, whereas the maximum accumulation occurred after 20 h of exposure to TPA. TPA also increased levels of MMTV-related RNA in the normal spleen cells of BALB/c and C57BL/6 mice. The level of RNA expression corresponding to MMTV-related sequences, however, was markedly elevated in EL-4 cells as compared with normal spleen cells. Southern blots of EL-4 cell DNA showed that the MMTV-related sequences were inserted into multiple locations of the EL-4 genome. Sequence analysis revealed that the MMTV-related cDNA clones included a part of the env gene and the right long terminal repeat of MMTV. However, the cDNA sequences were substantially different from published MMTV proviral sequences, most notably because of a contiguous deletion of 491 base pairs in the open reading frame within the U3 region.
通过差异杂交筛选用12 - O - 十四烷酰佛波醇 - 13 - 乙酸酯（TPA）处理的EL - 4细胞的cDNA文库，以寻找TPA诱导序列。最丰富的可诱导物种是一种与小鼠乳腺肿瘤病毒（MMTV）序列相似的序列。TPA处理30分钟后，对应于MMTV相关序列的mRNA诱导已经很明显，而最大积累发生在暴露于TPA 20小时后。TPA还增加了BALB / c和C57BL / 6小鼠正常脾细胞中MMTV相关RNA的水平。然而，与正常脾细胞相比，EL - 4细胞中对应于MMTV相关序列的RNA表达水平明显升高。EL - 4细胞DNA的Southern印迹显示，MMTV相关序列插入到EL - 4基因组的多个位置。序列分析表明，MMTV相关的cDNA克隆包括env基因的一部分和MMTV的右长末端重复序列。然而，cDNA序列与已发表的MMTV前病毒序列有很大不同，最明显的是因为U3区域内开放阅读框中有491个碱基对的连续缺失。
