Specific interactions and potential functions of human TAFII100.
Human transcription initiation factor TFIID contains the TATA-binding protein (TBP) and several TBP-associated factors (TAFs). To investigate the structural organization and function of TFIID, we have cloned and expressed a DNA encoding the third largest human TFIID subunit, hTAFII100. Immunoprecipitation studies demonstrate that hTAFII100 is an integral subunit that is associated with all transcriptionally-competent forms of TFIID. They further suggest that at least part of the N-terminal region lies on the surface of TFIID, while a C-terminal region containing conserved WD-40 repeats appears inaccessible. Both in vivo and in vitro assays indicate that hTAFII100 interacts strongly with the histone H4-related hTAFII80 and the histone H3-related hTAFII31, as well as a stable complex comprised of both hTAFII80 and hTAFII31. Apparently weaker interactions of hTAFII100 with TBP, hTAFII250, hTAFII28, and hTAFII20, but not hTAFII55, also have been observed. These results suggest a role for hTAFII100 in stabilizing interactions of TAFs, especially the histone-like TAFs, in TFIID. In addition, functional studies show that anti-hTAFII100 antibodies selectively inhibit basal transcription from a TATA-less initiator-containing promoter, relative to a TATA-containing promoter, suggesting a possible core promoter-specific function for hTAFII100.
Tao
Y
Y
Laboratory of Biochemistry and Molecular Biology, The Rockefeller University, New York, New York 10021, USA.
Guermah
M
M
Martinez
E
E
Oelgeschläger
T
T
Hasegawa
S
S
Takada
R
R
Yamamoto
T
T
Horikoshi
M
M
Roeder
R G
RG
D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D004268:DNA-Binding Proteins / Q000502:physiology*; D006367:HeLa Cells; D006801:Humans; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry; D011485:Protein Binding; D016415:Sequence Alignment; D035381:TATA-Binding Protein Associated Factors; D035362:Transcription Factor TFIID; D014157:Transcription Factors / Q000502:physiology*; D019473:Transcription Factors, TFII / Q000502:physiology*; D014158:Transcription, Genetic
D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D046911:Macromolecular Substances; D010455:Peptides; C100838:TAF5 protein, human; D035381:TATA-Binding Protein Associated Factors; D035362:Transcription Factor TFIID; D014157:Transcription Factors; D019473:Transcription Factors, TFII