The dual control of TFIIB recruitment by NC2 is gene specific.
Negative co-factor 2 (NC2) is a conserved eukaryotic complex composed of two subunits, NC2alpha (Drap1) and NC2beta (Dr1) that associate through a histone-fold motif. In this work, we generated mutants of NC2, characterized target genes for these mutants and studied the assembly of NC2 and general transcription factors on target promoters. We determined that the two NC2 subunits mostly function together to be recruited to DNA and regulate gene expression. We found that NC2 strongly controls promoter association of TFIIB, both negatively and positively. We could attribute the gene-specific repressor effect of NC2 on TFIIB to the C-terminal domain of NC2beta, and define that it requires ORF sequences of the target gene. In contrast, the positive function of NC2 on TFIIB targets is more general and requires adequate levels of the NC2 histone-fold heterodimer on promoters. Finally, we determined that NC2 becomes limiting for TATA-binding protein (TBP) association with a heat inducible promoter under heat stress. This study demonstrates an important positive role of NC2 for formation of the pre-initiation complex on promoters, under normal conditions through control of TFIIB, or upon activation by stress via control of TBP.
Department of Microbiology and Molecular Medicine, CMU, 1 rue Michel Servet 1211, Geneva 4, Switzerland.
Patrick
P
Masson
Elisa
E
Leimgruber
Sandrine
S
Creton
Martine A
MA
Collart
D019281:Dimerization; D005786:Gene Expression Regulation; D006360:Heat-Shock Proteins / Q000096:biosynthesis; D018869:Heat-Shock Response; D009154:Mutation; D020411:Oligonucleotide Array Sequence Analysis; D010750:Phosphoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development; D029701:Saccharomyces cerevisiae Proteins / Q000096:biosynthesis; D035581:Transcription Factor TFIIB / Q000378:metabolism*; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
C112591:HSP12 protein, S cerevisiae; D006360:Heat-Shock Proteins; D010750:Phosphoproteins; D021122:Protein Subunits; D012333:RNA, Messenger; D029701:Saccharomyces cerevisiae Proteins; D035581:Transcription Factor TFIIB; D014157:Transcription Factors; C075995:down-regulator of transcription 1