Identification, molecular cloning, and characterization of the sixth subunit of human transcription factor TFIIIC.
TFIIIC in yeast and humans is required for transcription of tRNA and 5 S RNA genes by RNA polymerase III. In the yeast Saccharomyces cerevisiae, TFIIIC is composed of six subunits, five of which are conserved in humans. We report the identification, molecular cloning, and characterization of the sixth subunit of human TFIIIC, TFIIIC35, which is related to the smallest subunit of yeast TFIIIC. Human TFIIIC35 does not contain the phosphoglycerate mutase domain of its yeast counterpart, and these two proteins display only limited homology within a 34-amino acid domain. Homologs of the sixth TFIIIC subunit are also identified in other eukaryotes, and their phylogenic evolution is analyzed. Affinity-purified human TFIIIC from an epitope-tagged TFIIIC35 cell line is active in binding to and in transcription of the VA1 gene in vitro. Furthermore, TFIIIC35 specifically interacts with the human TFIIIC subunits TFIIIC63 and, to a lesser extent, TFIIIC90 in vitro. Finally, we determined a limited region in the smallest subunit of yeast TFIIIC that is sufficient for interacting with the yeast TFIIIC subunit ScTfc1 (orthologous to TFIIIC63) and found it to be adjacent to and overlap the 34-amino acid domain that is conserved from yeast to humans.
Dumay-Odelot
Hélène
H
Institut Européen de Chimie et Biologie (I.E.C.B.), Université Bordeaux 2 Victor Ségalen, INSERM U869, rue Robert Escarpit, Pessac, F-33607, France.
Marck
Christian
C
Durrieu-Gaillard
Stéphanie
S
Lefebvre
Olivier
O
Jourdain
Sabine
S
Prochazkova
Martina
M
Pflieger
Aude
A
Teichmann
Martin
M
D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D017931:DNA Primers; D005455:Fluorescent Antibody Technique; D006801:Humans; D008969:Molecular Sequence Data; D010802:Phylogeny; D012320:RNA Polymerase III / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000145:classification / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D019474:Transcription Factors, TFIII / Q000737:chemistry / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D000098832:Transcription Factor TFIIIC
D017931:DNA Primers; D011994:Recombinant Proteins; D019474:Transcription Factors, TFIII; D000098832:Transcription Factor TFIIIC; D012320:RNA Polymerase III