Molecular and Cellular Biology, July 1999, p. 5050-5060, Vol. 19, No. 7
0270-7306/99/$04.00+0
Copyright © 1999, American Society for Microbiology. All rights reserved.


Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, 67404 Illkirch Cédex, C.U. de Strasbourg, France
Received 1 February 1999/Returned for modification 1 March 1999/Accepted 12 April 1999
Coexpression of the human TATA-binding protein (TBP)-associated
factor 28 (hTAFII28) with the altered-specificity mutant
TBP spm3 synergistically enhances transcriptional activation by the activation function 2 of the nuclear receptors (NRs) for estrogen and
vitamin D3 from a reporter plasmid containing a TGTA
element in mammalian cells. This synergy is abolished by mutation of
specific amino acids in the
2-helix of the histone fold in the
conserved C-terminal region of hTAFII28. Critical amino
acids are found on both the exposed hydrophilic face of this
helix and the hydrophobic interface with TAFII18. This
-helix of hTAFII28 therefore mediates multiple
interactions required for coactivator activity. We further show that
mutation of specific residues in the H1'
-helix of TBP either
reduces or increases interactions with hTAFII28. The mutations which reduce interactions with hTAFII28 do not
affect functional synergy, whereas the TBP mutation which increases
interaction with hTAFII28 is defective in its ability
to synergistically enhance activation by NRs. However, this TBP mutant
supports activation by other activators and is thus specifically
defective for its ability to synergize with hTAFII28.
Present address: European Molecular Biology Laboratory, 69012 Heidelberg, Germany.
Present address: Institut de Pharmacologie et de Biologie
Structurale, CNRS, UPR 9062, 31077 Toulouse, France.
This article has been cited by other articles:
| J. Bacteriol. | J. Virol. | Eukaryot. Cell |
|---|
| Microbiol. Mol. Biol. Rev. | Clin. Vaccine Immunol. | All ASM Journals |
|---|