Hanecak R, Pattengale P K, Fan H
Department of Molecular Biology and Biochemistry, University of California, Irvine 92717.
J Virol. 1988 Jul;62(7):2427-36. doi: 10.1128/JVI.62.7.2427-2436.1988.
Moloney murine leukemia virus (M-MuLV) is a replication-competent retrovirus which induces T-cell lymphoma in mice. The enhancer sequences present within the M-MuLV long terminal repeat (LTR) region of the proviral genome have been shown to influence the disease specificity of the virus strongly. We examined the contribution of the M-MuLV enhancers to the transcriptional activity and pathogenesis of M-MuLV by constructing LTRs containing heterologous enhancer elements. The simian virus 40 enhancer region (72- and 21-base-pair repeats) was inserted into the U3 region (at -150 base pairs) of the M-MuLV LTR (Mo + SV) and also into a deleted form of the LTR which lacks the M-MuLV enhancer sequences (delta Mo + SV). These chimeric LTRs were used to generate infectious M-MuLVs by transfection of corresponding proviral plasmids into mouse fibroblasts. The relative infectivities of Mo + SV and delta Mo + SV recombinant viruses as determined by rat XC cell plaque assay and reverse transcriptase assay were 60 to 70% of wild-type M-MuLV levels. To study the pathogenicity of these two recombinant viruses, we inoculated newborn NIH Swiss mice with either Mo + SV or delta Mo + SV M-MuLV. Both viruses induced disease more slowly than M-MuLV, which induces disease 2 to 4 months postinoculation. Mo + SV M-MuLV-inoculated animals became moribund at 3 to 13 months postinoculation, whereas delta Mo + SV M-MuLV-inoculated animals became moribund at 6 to 24 months postinoculation. The tumors induced by the two viruses were characterized histologically and molecularly. Mo + SV M-MuLV-induced tumors were primarily T-cell-derived lymphoblastic lymphomas containing extensive rearrangements of the T-cell receptor beta gene. In contrast, delta Mo + SV M-MuLV induced pre-B- and B-cell lymphoblastic lymphomas, B-cell-derived follicular-center cell lymphomas, and acute myeloid leukemia. The delta Mo + SV tumor DNAs from B-lineage tumors were typically rearranged at the immunoglobulin gene loci and contained germ line configurations of the T-cell receptor beta gene. Southern blot hybridization confirmed that the tumor DNAs contained the predicted Mo + SV M-MuLV or delta Mo + SV M-MuLV provirus.
莫洛尼鼠白血病病毒（M-MuLV）是一种具有复制能力的逆转录病毒，可在小鼠中诱发T细胞淋巴瘤。已证明原病毒基因组的M-MuLV长末端重复序列（LTR）区域内的增强子序列对病毒的疾病特异性有强烈影响。我们通过构建含有异源增强子元件的LTR，研究了M-MuLV增强子对M-MuLV转录活性和发病机制的贡献。将猿猴病毒40增强子区域（72和21碱基对重复序列）插入M-MuLV LTR的U3区域（在-150碱基对处）（Mo + SV），也插入缺乏M-MuLV增强子序列的LTR缺失形式（δMo + SV）。通过将相应的原病毒质粒转染到小鼠成纤维细胞中，利用这些嵌合LTR产生感染性M-MuLV。通过大鼠XC细胞空斑试验和逆转录酶试验测定，Mo + SV和δMo + SV重组病毒的相对感染性为野生型M-MuLV水平的60%至70%。为了研究这两种重组病毒的致病性，我们用Mo + SV或δMo + SV M-MuLV接种新生NIH瑞士小鼠。两种病毒诱发疾病的速度均比M-MuLV慢，M-MuLV在接种后2至4个月诱发疾病。接种Mo + SV M-MuLV的动物在接种后3至13个月濒死，而接种δMo + SV M-MuLV的动物在接种后6至24个月濒死。从组织学和分子水平对两种病毒诱发的肿瘤进行了特征分析。Mo + SV M-MuLV诱发的肿瘤主要是T细胞来源的淋巴母细胞淋巴瘤，含有T细胞受体β基因的广泛重排。相比之下，δMo + SV M-MuLV诱发前B细胞和B细胞淋巴母细胞淋巴瘤、B细胞来源的滤泡中心细胞淋巴瘤以及急性髓性白血病。来自B系肿瘤的δMo + SV肿瘤DNA通常在免疫球蛋白基因位点发生重排，并且含有T细胞受体β基因的种系构型。Southern印迹杂交证实肿瘤DNA含有预测的Mo + SV M-MuLV或δMo + SV M-MuLV原病毒。
