Durand D B, Kamoun M, Norris C A, Holbrook N J, Greengard J S, Crabtree G R, Kant J A
J Exp Med. 1986 Nov 1;164(5):1723-34. doi: 10.1084/jem.164.5.1723.
The gibbon ape leukemia virus (GaLVSF)-infected T cell line, MLA 144, was established from the lymphoma of a gibbon ape. The cell line constitutively expresses IL-2 and its receptor, implying that an autocrine mechanism could be responsible for or contribute toward its growth. To explore the mechanism of constitutive IL-2 expression in MLA 144, we have isolated and characterized cosmid clones representing a normal and a doubly inserted IL-2 allele in this cell line. The map of the normal MLA 144 IL-2 allele closely resembles that of the normal human IL-2 gene. The abnormal allele contains a 3' insertion that is a GaLVSF provirus with two long terminal repeats (LTR) and an internal 3.25 kb deletion. At the 5' end of the abnormal allele is a second insertion that DNA sequencing showed to be an isolated GaLVSF LTR with a transcriptional orientation opposing that of the IL-2 gene. We demonstrate by Northern blotting analysis that the vast majority of transcripts are from the abnormal allele, implying that one or both retroviral insertions are responsible for constitutive expression of the allele.
长臂猿白血病病毒（GaLVSF）感染的T细胞系MLA 144是从一只长臂猿的淋巴瘤中建立的。该细胞系组成性表达白细胞介素-2（IL-2）及其受体，这意味着自分泌机制可能对其生长起作用或有促进作用。为了探究MLA 144中IL-2组成性表达的机制，我们分离并鉴定了代表该细胞系中正常和双插入IL-2等位基因的黏粒克隆。正常的MLA 144 IL-2等位基因图谱与正常人IL-2基因的图谱非常相似。异常等位基因包含一个3'端插入，是一个带有两个长末端重复序列（LTR）的GaLVSF前病毒以及一个3.25 kb的内部缺失。在异常等位基因的5'端是第二个插入，DNA测序显示其为一个孤立的GaLVSF LTR，转录方向与IL-2基因相反。我们通过Northern印迹分析证明，绝大多数转录本来自异常等位基因，这意味着一个或两个逆转录病毒插入对该等位基因的组成性表达负责。
