Rabson A B, Steele P E, Garon C F, Martin M A
Nature. 1983;306(5943):604-7. doi: 10.1038/306604a0.
Mammalian cells contain multiple copies of endogenous type C retroviral DNA sequences. Among these sequences are complete, potentially infectious proviruses, proviral DNA that is expressed only in the form of viral antigens, retroviral segments that may contribute portions of envelope (env) genes during the generation of recombinant polytropic viruses, and many subgenomic viral DNA segments that may not be expressed at all. We have previously reported the identification and molecular cloning of type C retroviral sequences from human DNA and have shown that the partial nucleotide and deduced amino acid sequences of one of the clones obtained (lambda 51) are homologous to Moloney MuLV (MoMuLV) in the gag and pol regions. The lambda 51 clone as well as several others isolated from a human DNA library contained approximately 4.3 kilobases (kb) of retroviral sequences, were deleted in the env region, and were flanked by tandem repeats unlike the long terminal repeats (LTRs) typically found in proviral DNAs (P.E.S., in preparation). We describe here the characterization of a full-length human retroviral clone (lambda 4-1) containing LTR elements as well as a putative env region. DNA-RNA hybridization experiments reveal that human cells contain species of poly(A)+ RNA that anneal to segments of the full-length retroviral DNA clone.
哺乳动物细胞含有多个拷贝的内源性C型逆转录病毒DNA序列。在这些序列中，有完整的、可能具有感染性的前病毒，仅以病毒抗原形式表达的前病毒DNA，在重组多嗜性病毒产生过程中可能贡献包膜（env）基因部分片段的逆转录病毒片段，以及许多可能根本不表达的亚基因组病毒DNA片段。我们之前报道了从人类DNA中鉴定和分子克隆C型逆转录病毒序列，并表明所获得的一个克隆（λ51）的部分核苷酸和推导氨基酸序列在gag和pol区域与莫洛尼鼠白血病病毒（MoMuLV）同源。λ51克隆以及从人类DNA文库中分离出的其他几个克隆包含约4.3千碱基（kb）的逆转录病毒序列，在env区域缺失，并且两侧是串联重复序列，这与通常在前病毒DNA中发现的长末端重复序列（LTRs）不同（P.E.S.，正在准备中）。我们在此描述一个包含LTR元件以及推定env区域的全长人类逆转录病毒克隆（λ4 - 1）的特征。DNA - RNA杂交实验表明，人类细胞含有与全长逆转录病毒DNA克隆片段退火的多聚（A）+ RNA种类。
