CHARACTERIZATION OF ENDOGENOUS ECOTROPIC AND XENOTROPIC MURINE LEUKEMIA VIRUSES

水貂细胞病灶形成病毒是一种双嗜性小鼠白血病 从白血病小鼠组织中分离出的病毒(MuLV)。这些 根据病毒的能力将其分为两类 加速AKR小鼠胸腺淋巴瘤的发生。两类MCF 病毒由生态型小鼠细小病毒和内源性病毒重组而产生 与MCVF相关的环境序列。白血病MCF MuLV(1类)可复制 在胸腺中高效生长，而非白血病(II类)生长 胸腺不好。长末端重复序列(LTRs)已经被证明是 参与与组织特异性和疾病诱导相关的 导致白血病的MuLV；也是存在于Gag、Pol区或env区的序列 已被证明是表达最大的白血病原性所必需的。 为了研究与病毒性白血病发生有关的MCF-MULV序列， 白血病和非白血病MCF-13基因的分子克隆 获得了McF-111AMuLV，并测定了LTRS，3‘的核苷酸序列。 确定了POL和5‘env区。关于比较序列的几个结果 分析表明，MCF-13的LTR区和3‘POL区存在差异 和MCF-111A型MVDNA。与MCF-13相关的LTR值密切相关 与异质性MUV中存在的序列相同，而MCF-111a的LTR序列 与生态型前病毒LTR1个碱基不同外，其余均相同。12BP 存在核苷酸拉伸，这是白血病MCF MuLV的特征 MCF2-13位于3‘Pol区，而MCF-111a缺失。不是 MCF-13和MCF-111AMuLV之间的序列差异显著 包膜区域中的DNA。这些结果表明，导致白血病的 MCF-13的潜在功能可能存在于LTR和3‘POL序列中。

Mink cell focus forming (MCF) viruses are dualtropic murine leukemia viruses (MuLVs) which have been isolated from leukemic mouse tissue. These viruses have been divided into two classes based on their ability to accelerate the onset of thymic lymphomas in AKR mice. Both classes of MCF viruses arise by recombination involving ecotropic MuLV and endogenous MCVF-related env sequences. Leukemogenic MCF MuLVs (class 1) replicate efficiently in the thymus whereas the non-leukemogenic (class II) grow poorly in the thymus. Long terminal repeats (LTRs) have been shown to be involved in tissue-specificity and disease induction associated with leukemogenic MuLVs; also, sequences present in the gag, pol, or env regions have been shown to be necessary for expression of maximum leukemogenicity. To study the sequences of MCF-MULVs involved in viral leukemogenesis, molecularly cloned DNAs of leukemogenic MCF-13 and non-leukemogenic MCF-111A MuLVs were obtained and the nucleotide sequences of the LTRs, 3' pol and 5' env regions determined. The reults of compartive sequence analysis indicated difference in the LTR and 3' pol regions between MCF-13 and MCF-111A MuLV DNAs. The LTR associated with MCF-13 was closely related to that present in xenotropic MuLVs, whereas the LTR sequence of MCF-111A that identical except for 1 bp to the ecotropic proviral LTR. A 12 bp nucleotide stretch, characteristic of leukemogenic MCF MuLVs, was present in MCF2-13 in the 3' pol region but was lacking in MCF-111A. No significant sequence divergence was seen between MCF-13 and MCF-111A MuLV DNAs in the env region. These results suggest that the leukemogenic potential of MCF-13 may reside in LTR and 3' pol sequences.