Wang W B, Bikel I, Marsilio E, Newsome D, Livingston D M
Dana-Farber Cancer Institute, Boston, Massachusetts 02115.
J Virol. 1994 Oct;68(10):6180-7. doi: 10.1128/JVI.68.10.6180-6187.1994.
Simian virus 40 (SV40) small t antigen (t) can activate transcription from certain RNA polymerase II and III promoters (M. Loeken, I. Bikel, D. M. Livingston, and J. Brady, Cell 55:1171-1177, 1988). Here we report a new function of t, its ability to repress human c-fos promoter and AP-1 transcriptional activity in CV-1P cells. This function is the product of a discrete N-terminal domain of t, because the large T antigen (T)/t-common polypeptide, which contains only the first 82 amino acids common to both T and t of SV40, was, like the intact protein, an active repressor. The data further suggest that the t- and T/t-common-mediated repression of c-fos expression was most likely manifest at the level of transcription. In keeping with the possibility that t affects the expression of the genomic c-fos promoter, it also led to repression of AP-1 formation. Thus, SV40 is both an activator and a repressor of transcription. Its ability to inhibit c-fos expression should be considered in light of the natural history of SV40 in its natural host.
猴病毒40（SV40）小t抗原（t）可激活某些RNA聚合酶II和III启动子的转录（M. Loeken、I. Bikel、D. M. Livingston和J. Brady，《细胞》55:1171 - 1177，1988年）。在此我们报告t的一项新功能，即其在CV - 1P细胞中抑制人c - fos启动子和AP - 1转录活性的能力。此功能是t一个离散N端结构域的产物，因为大T抗原（T）/t共同多肽，它仅包含SV40的T和t共有的前82个氨基酸，与完整蛋白一样，是一种活性阻遏物。数据进一步表明，t和T/t共同介导的对c - fos表达的抑制很可能在转录水平体现。鉴于t影响基因组c - fos启动子表达的可能性，它还导致AP - 1形成受到抑制。因此，SV40既是转录激活剂又是转录阻遏物。应根据SV40在其天然宿主中的自然史来考虑其抑制c - fos表达的能力。
