Abstract
Yeast transcription factor IIIC (TFIIIC) plays a key role in assembling the transcription initiation factor TFIIIB on class III genes after TFIIIC-DNA binding. The second largest subunit of TFIIIC, tau131, is thought to initiate TFIIIB assembly by interacting with Brf1/TFIIIB70. In this work, we have analyzed a TFIIIC mutant (tau131-DeltaTPR2) harboring a deletion in tau131 removing the second of its 11 tetratricopeptide repeats. Remarkably, this thermosensitive mutation was selectively suppressed in vivo by overexpression of B"/TFIIIB90, but not Brf1 or TATA-binding protein. In vitro, the mutant factor preincubated at restrictive temperature bound DNA efficiently but lost transcription factor activity. The in vitro transcription defect was abolished at high concentrations of B" but not Brf1. Copurification experiments of baculovirus-expressed proteins confirmed a direct physical interaction between tau131 and B". tau131, therefore, appears to be involved in the recruitment of both Brf1 and B".
Publication types
-
Research Support, Non-U.S. Gov't
-
Research Support, U.S. Gov't, P.H.S.
MeSH terms
-
Amino Acid Motifs
-
Amino Acid Sequence
-
Animals
-
DNA-Binding Proteins / genetics
-
DNA-Binding Proteins / metabolism
-
Genes, Reporter
-
Heparin / pharmacology
-
Humans
-
Molecular Sequence Data
-
Mutation
-
Protein Subunits
-
Recombinant Fusion Proteins / metabolism
-
Saccharomyces cerevisiae / drug effects
-
Saccharomyces cerevisiae / growth & development
-
Saccharomyces cerevisiae / metabolism*
-
Saccharomyces cerevisiae Proteins / chemistry
-
Saccharomyces cerevisiae Proteins / genetics
-
Saccharomyces cerevisiae Proteins / metabolism
-
Sequence Alignment
-
TATA-Binding Protein Associated Factors*
-
Temperature
-
Transcription Factor TFIIIB
-
Transcription Factor TFIIIC
-
Transcription Factors / chemistry
-
Transcription Factors / genetics
-
Transcription Factors / metabolism*
-
Transcription Factors, TFIII / chemistry
-
Transcription Factors, TFIII / genetics
-
Transcription Factors, TFIII / metabolism*
Substances
-
BRF1 protein, S cerevisiae
-
BRF1 protein, human
-
DNA-Binding Proteins
-
Protein Subunits
-
Recombinant Fusion Proteins
-
Saccharomyces cerevisiae Proteins
-
TATA-Binding Protein Associated Factors
-
Transcription Factor TFIIIB
-
Transcription Factors
-
Transcription Factors, TFIII
-
Transcription Factor TFIIIC
-
Heparin