Koizumi A, Tsukada M, Kamiyama S
Department of Hygiene, Akita University School of Medicine, Japan.
Tohoku J Exp Med. 1992 Jul;167(3):171-80. doi: 10.1620/tjem.167.171.
Mouse mammary tumor virus (MMTV) is a retrovirus with a life cycle that remains to be elucidated. In establishing Mtv-4 congenic mice, an extra copy of the MMTV provirus was found specifically in the skin of both sexes of SHN mice but not in C3H/He mice. This extra copy was not, however, found in other normal tissues such as brain, lung, liver, spleen, kidney, uterus, testis, and mammary glands from SHN or C3H/He mice. In the skin of SHN mice, an 11-kb DNA fragment, which approximates in size to the entire MMTV genome, was detected in undigested high-molecular weight DNA. This unique MMTV provirus was shown to be transmitted horizontally from SHN mice to exogenous-MMTV-free C3H/He mice through nursing. The virus is thus concluded to be exogenous. Clusters of MMTV type A particles were found in sebaceous glands by electronmicroscopic examination. The present findings indicates that exogenous MMTV may be stably maintained in the skin as an unintegrated provirus during its life cycle.
小鼠乳腺肿瘤病毒（MMTV）是一种逆转录病毒，其生命周期尚待阐明。在培育Mtv - 4同源基因小鼠的过程中，发现MMTV前病毒的一个额外拷贝专门存在于SHN小鼠两性的皮肤中，而在C3H/He小鼠中则未发现。然而，在来自SHN或C3H/He小鼠的其他正常组织如脑、肺、肝、脾、肾、子宫、睾丸和乳腺中未发现这个额外拷贝。在SHN小鼠的皮肤中，在未消化的高分子量DNA中检测到一个大小约为整个MMTV基因组的11kb DNA片段。这种独特的MMTV前病毒被证明通过哺乳从SHN小鼠水平传播到无外源性MMTV的C3H/He小鼠。因此，该病毒被认为是外源性的。通过电子显微镜检查在皮脂腺中发现了A型MMTV颗粒簇。目前的研究结果表明，外源性MMTV在其生命周期中可能作为未整合的前病毒稳定地存在于皮肤中。
