Open AccessHuman TAF II 28 interacts with the human T cell leukemia virus type I Tax transactivator and promotes its transcriptional activity
Author(s) -
Cécile Caron,
Gabrielle Mengus,
Veronica Dubrowskaya,
Armelle Roisin,
Irwin Davidson,
Pierre Jalinot
Publication year - 1997
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.94.8.3662
Subject(s) - transactivation , human t lymphotropic virus 1 , leukemia , biology , virus , virology , microbiology and biotechnology , genetics , transcription factor , gene , t cell leukemia
The Tax protein encoded by human T cell leukemia virus type I transactivates the viral promoter by forming a complex with several cellular factors bound to three repeats of a specific upstream regulatory sequence. We have shown that transactivation by Tax was correlated with its ability to interact with the C-terminal moiety of the TATA box-binding protein (TBP). In the present study, the ability of Tax to interact with several human TBP-associated factors (TAFII s) was analyzed. We show that Tax interacts selectively with hTAFII 28 in transfected HeLa cells. A direct interaction between Tax and hTAFII 28 was also observedin vitro with purified proteins. In transient expression studies we show that overexpression of hTAFII 28 significantly increased transactivation by Tax, both in the absence and in the presence of overexpressed TBP. The ability of hTAFII 28 to potentiate transactivation correlated with the ability of Tax to interact with hTAFII 28 and also with the ability of hTAFII 28 to interact with TBP. Coexpression of TBP and hTAFII 28 resulted in an additive increase in transactivation by Tax. From these observations we propose that transcriptional activation by Tax involves multiple interactions with TFIID via its TBP and hTAFII 28 subunits.