Author:
Fujii M,Tsuchiya H,Chuhjo T,Akizawa T,Seiki M
Abstract
Tax1 of human T-cell leukemia virus type 1 (HTLV-1) is a transcriptional activator for viral gene expression and is also a transforming protein through inducing the expression of several cellular genes under the control of mitogenic signals. We identified the CArG boxes as a Tax1-responsive cis-acting element for the cellular immediate early genes c-fos, egr-1, and egr-2. Using a chimeric protein consisting of the CArG-binding factor p67SRF and the heterologous DNA-binding domain of a yeast transcription factor GAL4, we demonstrated that Tax1 activates the transcriptional activity of p67SRF through the GAL4-binding site. The carboxy-terminal half of p67SRF, which lacks domains for DNA-binding, dimerization, and ternary complex formation with p62TCF, was sufficient for the activation by Tax1. Tax1 produced in Escherichia coli bound p67SRF in vitro. The complex formation in vivo was also indicated by the finding that the acidic activation domain of VP16, by fusion to p67SRF, can complement the transcriptional activation function of a mutant Tax1 in trans. Thus, Tax1 activates CArG-mediated transcription without mitogenic signals through interaction with a CArG-binding factor, p67SRF. This must be one of the primary steps by which Tax1 causes aberration in growth control of the infected cells.
Publisher
Cold Spring Harbor Laboratory
Subject
Developmental Biology,Genetics
Reference56 articles.
1. Four regulatory elements in the human c-fos promoter mediate transactivation by HTLV-1 Tax protein.;Oncogene,1991
2. Trans-activation of Krox-20 and Krox-24 promoters by the HTLV-1 Tax protein through common regulatory elements.;Oncogene,1991
3. Binding of the HTLV-1 transactivator to the inducible 21bp enhancer is mediated by the cellular factor HEB1.;EMBO J.,1991
4. Identification of the gene responsible for human T-cell leukaemia virus transcriptional regulation
5. SV40 large tumor antigen forms a specific complex with the product of the retinoblastoma susceptibility gene.;Cell,1988
Cited by
236 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献