STRUCTURAL AND FUNCTIONAL ANALYSIS OF ENDOGENOUS PROVIRUSES OF MICE

小鼠基因组含有至少50个拷贝的小鼠白血病病毒 （MuLV）相关的DNA，其中大多数是有缺陷的。 重组 不同感染性和缺陷性MuLV DNA结果的序列之间 在产生新的MuLV中，包括淋巴瘤原性水貂细胞， 成灶性（MCF）病毒。 该项目的主要目标是：1） 确定内源性MuLV序列与感染性 MuLV; 2）研究重组MCF病毒的产生;以及3） 鉴定有助于MCF MuLV白血病发生的序列。 从BALB/c中克隆了两个独特的逆转录病毒DNA，B-26和B-60 小鼠基因组。 这些DNA彼此之间有远亲关系， 在gag、pol和env区域中的感染性MuLV前病毒。 核苷酸 序列分析表明，B-26和B-60 DNA含有不同的 逆转录病毒样LTR，不同于MuLV LTR。 比较分布 B-26和B-60相关序列和感染性MuLV前病毒的研究 在一系列啮齿类动物DNA中，发现B-26和B-60基因家族是 在老鼠的基因组中得到了扩增。 研究MCF病毒潜在重组伴侣的结构 起源，内源性MCF env相关的7.2 kb mRNA的2.0 kb cDNA片段 克隆并测定其核苷酸序列。 序列 分析表明在env区有1.2kb的缺失。 发现了cDNA 与先前克隆的内源性MCF相关基因密切相关 含有相同的env缺失的前病毒，因此表明， 后一个DNA家族可能作为可能的前体的模板， MCF病毒。 致白血病的MCF MuLV在其基因组中含有独特的12 bp序列， pol基因的整合酶编码区。 为了研究这个 在白血病发生中的核苷酸延伸，12 bp被删除， 从MCF 13前病毒DNA进行寡核苷酸诱变。 获得的病毒 使用突变DNA进行转染研究， AKR小鼠测试MCF病毒基因组是否保留其致白血病性 在不存在12 bp序列的情况下，

Mouse genome contains at least 50 copies of murine leukemia viral (MuLV)-related DNAs, the majority of which are defective. Recombination between sequences of different infectious and defective MuLV DNAs results in the generation of novel MuLVs including lymphomagenic mink cell focus-forming (MCF) viruses. The main goals of this project are: 1) to determine the relatedness between endogenous MuLV sequences and infectious MuLVs; 2) to study generation of recombinant MCF viruses; and 3) to identify sequences contributing to leukemogenicity of MCF MuLVs. Two unique retroviral DNAs, B-26 and B-60, were cloned from the BALB/c mouse genome. The DNAs were distantly related to each other and known infectious MuLV proviruses in the gag, pol and env regions. Nucleotide sequence analysis indicated that B-26 and B-60 DNAs contained different retroviral-like LTRs, distinct from MuLV LTRs. Comparative distribution studies of B-26- and B-60-related sequences and infectious MuLV proviruses in a series of rodent DNAs indicated that B-26 and B-60 gene families were ancient and had amplified in the mouse genome. To study the structure of potential recombinational partners in MCF virus genesis, a 2.0 kb cDNA segment of endogenous MCF env-related 7.2 kb mRNA species was cloned and its nucleotide sequence determined. Sequence analysis indicated a 1.2 kb deletion in the env region. The cDNA was found to be closely related to a previously cloned endogenous MCF-related provirus which contained an identical env deletion, thus indicating that the latter DNA family might serve as templates to possible precursors of MCF viruses. Leukemogenic MCF MuLVs contain a unique 12 bp sequence in the integrase-coding region of the pol gene. To study the role of this nucleotide stretch in leukemogenesis the 12 bp were deleted by oligonucleotide mutagenesis from MCF13 proviral DNA. The virus obtained from transfection studies using the mutant DNA has been injected into young AKR mice to test whether the MCF viral genome retains its leukemogenic potential in the absence of the 12 bp sequence.