A chimeric subunit of yeast transcription factor IIIC forms a subcomplex with tau95.
The multisubunit yeast transcription factor IIIC (TFIIIC) is a multifunctional protein required for promoter recognition, transcription factor IIIB recruitment, and chromatin antirepression. We report the isolation and characterization of TFC7, an essential gene encoding the 55-kDa polypeptide, tau55, present in affinity-purified TFIIIC. tau55 is a chimeric protein generated by an ancient chromosomal rearrangement. Its C-terminal half is essential for cell viability and sufficient to ensure TFIIIC function in DNA binding and transcription assays. The N-terminal half is nonessential and highly similar to a putative yeast protein encoded on another chromosome and to a cyanobacterial protein of unknown function. Partial deletions of the N-terminal domain impaired tau55 function at a high temperature or in media containing glycerol or ethanol, suggesting a link between PolIII transcription and metabolic pathways. Interestingly, tau55 was found, together with TFIIIC subunit tau95, in a protein complex which was distinct from TFIIIC and which may play a role in the regulation of PolIII transcription, possibly in relation to cell metabolism.
Manaud
N
N
Service de Biochimie et de Génétique Moléculaire, CEA/Saclay, F-91191 Gif-sur-Yvette Cedex, France.
Arrebola
R
R
Buffin-Meyer
B
B
Lefebvre
O
O
Voss
H
H
Riva
M
M
Conesa
C
C
Sentenac
A
A
D000595:Amino Acid Sequence; D004258:DNA Polymerase III / Q000235:genetics; D004271:DNA, Fungal / Q000302:isolation & purification / Q000378:metabolism; D015321:Gene Rearrangement; D008969:Molecular Sequence Data; D008970:Molecular Weight; D016366:Open Reading Frames; D011487:Protein Conformation; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000302:isolation & purification; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D017384:Sequence Deletion; D014157:Transcription Factors / Q000235:genetics*; D019474:Transcription Factors, TFIII; D014158:Transcription, Genetic; D000098832:Transcription Factor TFIIIC
D004271:DNA, Fungal; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; C112471:TFC1 protein, S cerevisiae; D014157:Transcription Factors; D019474:Transcription Factors, TFIII; D000098832:Transcription Factor TFIIIC; D004258:DNA Polymerase III