CHARACTERIZATION OF ENDOGENOUS ECOTROPIC AND XENOTROPIC MURINE LEUKEMIA VIRUSES

貂细胞灶形成（MCF）病毒是双嗜性小鼠白血病 病毒（MuLV），其已经从白血病小鼠组织中分离。 这些 根据病毒的能力， 加速AKR小鼠胸腺淋巴瘤的发病。 两类MCF 病毒通过涉及亲嗜性MuLV和内源性MuLV的重组而产生。 MCVF相关env序列。 致白血病MCF MuLV（1类）重复检测 在胸腺中有效，而非白血病（II类）生长 在胸腺里很糟糕 长末端重复序列（LTR）已被证明是 参与组织特异性和疾病诱导， 致白血病MuLV;还有，存在于gag、pol或env区的序列 已经显示对于表达最大的致白血病性是必需的。 为了研究参与病毒性白血病发生的MCF-MULV序列， 致白血病MCF-13和非致白血病MCF-13的分子克隆DNA 获得MCF-111 A MuLV，并将LTR的核苷酸序列， pol和5 ′ env区。 比较序列的结果 分析表明，MCF-13细胞之间的LTR和3' pol区域存在差异， 和MCF-111A MuLV DNA。 与MCF-13相关的LTR密切相关， 异嗜性MuLV中存在的LTR序列，而MCF-111 A的LTR序列 除了与亲嗜性前病毒LTR的1个bp外，其余均相同。 A 12 bp 存在致白血病MCF MuLV的特征性核苷酸延伸 在MCF-2 -13的3 ′ pol区，但在MCF-111 A中缺乏。 没有 在MCF-13和MCF-111 A MuLV之间观察到显著的序列差异 env区的DNA。 这些结果表明， MCF-13的潜力可能在于LTR和3' pol序列。

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.