ORGANIZATION AND EXPRESSION OF EARLY GENES OF SIMIAN-VIRUS 40
ORGANIZATION AND EXPRESSION OF EARLY GENES OF SIMIAN-VIRUS 40
复制标题
DOI：
10.1073/pnas.75.1.117
复制
发表时间：
1978-01-01
影响因子：
11.1
通讯作者：
BERG, P
中科院分区：
文献类型：
--
作者：
CRAWFORD, LV;COLE, CN;BERG, P
SV-40的早期区编码至少2种与免疫相关的多肽：大t和小t，表观分子量分别为9万-10万和1.5万-2万。由于小t与大t共享含有蛋氨酸的色氨酸肽，这两种多肽可能部分由共同的核苷酸序列编码。为了确定DNA中大t和小t的编码序列，我们用SV-40的野生型和缺失突变体感染[非洲绿猴肾]CV-1细胞后检测了这些蛋白的产生。早期区域远端部分的缺失改变了大t的结构，但没有改变小t的结构；但在地图坐标0.59和0.55之间的区域内删除会导致小t和正常大t的改变或缺失。这些发现被一个模型合理化，该模型提出存在2个早期mRNA， 1个编码大t，另一个编码小t。两种mRNA几乎跨越整个早期区域；而编码large-T的mRNA缺少图谱坐标0.59 ~ 0.54之间的核苷酸序列。Small-t可能是从较大的2mrna翻译过来的，从其5'末端或其附近开始，并在约图谱坐标0.54处的终止密码子处终止。Large-T是从较短的mRNA翻译过来的，从相同的启动密码子开始，并且，由于在0.54处删除了终止密码子，翻译继续到在0.18或接近图谱位置的终止密码子。
The early region of SV-40 codes for at least 2 immunologically related polypeptides: large-T and small-t, with apparent MW of 90,000-100,000 and 15,000-20,000, respectively. Because small-t shares methionine-containing tryptic peptides with large-T, the 2 polypeptides are probably coded, in part, by a common nucleotide sequence. To locate the coding sequences for large-T and small-t in the DNA, the production of these proteins was examined after infection of [African green monkey kidney] CV-1 cells with wild-type and deletion mutants of SV-40. A deletion at the distal portion of the early region alters the structure of large-T but not of small-t; but deletions within the region between map coordinates 0.59 and 0.55 result in an alteration or absence of small-t and a normal large-T. These findings were rationalized by a model that proposes the existence of 2 early mRNA, 1 coding for large-T and the other for small-t. Both mRNA span virtually the entire early region; but the mRNA coding for large-T lacks the nucleotide sequence between map coordinates 0.59 and 0.54. Small-t is probably translated from the larger of the 2 mRNA, beginning at or near its 5'' end and terminating at a termination codon at about map coordinate 0.54. Large-T is translated from the shorter mRNA, beginning at the same initiator codon, and, because of the deletion of the terminator codon at 0.54, translation proceeds to the terminator codon at or near map position 0.18.