Open AccessMultiple Roles of the τ131 Subunit of Yeast Transcription Factor IIIC (TFIIIC) in TFIIIB Assembly
Author(s) -
Hélène DumayOdelot,
Joël Acker,
Rosalía Arrebola,
A Sentenac,
Christian Marck
Publication year - 2002
Publication title -
molecular and cellular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.14
H-Index - 327
eISSN - 1067-8824
pISSN - 0270-7306
DOI - 10.1128/mcb.22.1.298-308.2002
Subject(s) - transcription factor , biology , general transcription factor , transcription (linguistics) , rna polymerase iii , transcription factor ii a , protein subunit , dna binding protein , dna , microbiology and biotechnology , genetics , promoter , gene , gene expression , polymerase , linguistics , philosophy , rna dependent rna polymerase
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".