Rice N R, Stephens R M, Burny A, Gilden R V
Virology. 1985 Apr 30;142(2):357-77. doi: 10.1016/0042-6822(85)90344-7.
The DNA sequence of the gag and pol regions of a provirus cloned from a bovine tumor is presented. In order to confirm these results the sequence of portions of a second clone, derived from a virus-producing cell line, was also determined. The gag gene was found to consist of 1179 nucleotides, which probably encode only three proteins: an N-terminal protein of 109 amino acids, a major core protein (p24) of 215 amino acids, and a nucleic acid binding protein (p12) of 69 residues. An open reading frame, whose translated product showed clear homology to the avian and murine proteases, was found beginning immediately upstream of the 3' end of gag. Following this protease region, a third long open reading frame, encoding 852 amino acids, showed clear homology to both avian and murine pol genes. The mechanism of translation of the protease and pol gene products cannot be predicted with certainty. Like Moloney murine leukemia virus (M-MuLV), BLV has a termination signal at the 3' end of gag, but unlike M-MuLV the protease is in a different reading frame. Like Rous sarcoma virus (RSV), BLV has a termination signal at the 3' end of the protease region and the reverse transcriptase is in a different (i.e., the third) reading frame. Possible translation mechanisms are discussed. Finally, the BLV gag and pol gene products are highly related to those of the human T-cell leukemia virus (HTLV); relatedness varied from 37% amino acid identities within the N terminal gag protein to 54% within the nucleic acid binding protein. Highly significant homology with both murine and avian type-C proteins was found within p24, p12, and the putative protease, reverse transcriptase, and endonuclease. Based on this homology, the BLV-HTLV family of viruses appears about equally distantly related to murine and avian type-C viruses.
本文展示了从牛肿瘤中克隆出的前病毒gag和pol区域的DNA序列。为了证实这些结果，还测定了来自病毒产生细胞系的第二个克隆部分的序列。发现gag基因由1179个核苷酸组成，可能仅编码三种蛋白质：一个109个氨基酸的N端蛋白、一个215个氨基酸的主要核心蛋白（p24）和一个69个残基的核酸结合蛋白（p12）。在gag 3'端紧邻上游处发现了一个开放阅读框，其翻译产物与禽和鼠类蛋白酶有明显同源性。在这个蛋白酶区域之后，第三个长开放阅读框编码852个氨基酸，与禽和鼠类pol基因均有明显同源性。蛋白酶和pol基因产物的翻译机制尚不能确切预测。与莫洛尼鼠白血病病毒（M-MuLV）一样，BLV在gag的3'端有一个终止信号，但与M-MuLV不同的是，蛋白酶处于不同的阅读框。与劳氏肉瘤病毒（RSV）一样，BLV在蛋白酶区域的3'端有一个终止信号，逆转录酶处于不同（即第三个）阅读框。文中讨论了可能的翻译机制。最后，BLV的gag和pol基因产物与人类T细胞白血病病毒（HTLV）的基因产物高度相关；N端gag蛋白内的氨基酸同一性为37%，核酸结合蛋白内为54%。在p24、p12以及推定的蛋白酶、逆转录酶和核酸内切酶中发现与鼠类和禽类C型蛋白有高度显著的同源性。基于这种同源性，BLV-HTLV病毒家族与鼠类和禽类C型病毒的亲缘关系似乎大致相同。
