Transcriptional activation and self-association in yeast: protein-protein dimerization as a pleiotropic mechanism of HTLV-I Tax function
Jin, D.Y.; Jeang, K.T.
Leukemia 11 Suppl. 3: 3-6
1997
ISSN/ISBN: 0887-6924 PMID: 9209279 Document Number: 470205
The yeast one-hybrid and two-hybrid systems for the detection of protein-DNA and protein-protein interactions were used as an in vivo approach to investigate the functional characteristics of HTLV-1 Tax expressed in yeast. Tax, when targeted to the upstream activating sequence (UAS) via the DNA-binding domain of Gal4 (Gal4BD), was found to activate a minimal promoter in yeast, indicating the presence of a functionally intact activation domain. Using the two-hybrid assay in which Tax was fused to either Gal4BD or Gal4 activation domain (Gal4AD), we demonstrate that Tax self-associates in the nucleus of yeast cells. Mutational analysis was performed to delineate the functional domain(s) necessary for Tax-mediated trans-activation and self-association. Based on our results, we propose a pleiotropic mechanism in which Tax facilitates protein-protein dimerization of various cellular partners.