感染大鼠细胞中的小鼠乳腺肿瘤病毒DNA：未整合形式的特征

Mouse mammary tumor virus DNA in infected rat cells: characterization of unintegrated forms.

作者信息

Ringold G M, Yamamoto K R, Shank P R, Varmus H E

出版信息

Cell. 1977 Jan;10(1):19-26. doi: 10.1016/0092-8674(77)90135-0.

Abstract

Mouse mammary tumor virus (MMTV) DNA in chronically infected rat hepatoma cells is maintained in both the integrated and unintegrated state. Fractionation of DNA by the procedure of Hirt (1967) as well as by sedimentation through alkaline sucrose suggests that about two thirds of the viral DNA is associated with high molecular weight cell DNA. The remainder of the viral DNA is unintegrated and is present primarily as linear or open circular duplexes consisting of a genome-length strand complementary to the viral RNA ("minus" strand) and "plus" strands of subgenomic length. Approximately 20% of the unintegrated MMTV DNA is present as double-stranded, covently closed circles (form I) with a molecular weight of 6 X 10(6) daltons. Form I viral DNA is found primarily in the nucleus, whereas the open forms are both nuclear and cytoplasmic.

摘要

慢性感染大鼠肝癌细胞中的小鼠乳腺肿瘤病毒（MMTV）DNA以整合态和非整合态两种形式存在。通过Hirt（1967）方法对DNA进行分级分离以及通过碱性蔗糖沉降分析表明，约三分之二的病毒DNA与高分子量细胞DNA相关联。其余的病毒DNA未整合，主要以线性或开环双链体形式存在，由与病毒RNA互补的基因组长度链（“负”链）和亚基因组长度的“正”链组成。大约20%的未整合MMTV DNA以分子量为6×10⁶道尔顿的双链共价闭合环（形式I）存在。形式I病毒DNA主要存在于细胞核中，而开放形式则同时存在于细胞核和细胞质中。