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TIF‐IA, the factor mediating growth‐dependent control of ribosomal RNA synthesis, is the mammalian homolog of yeast Rrn3p
Author(s) -
Bodem Jochen,
Dobreva Gergana,
HoffmannRohrer Urs,
Iben Sebastian,
Zentgraf Hanswalter,
Delius Hajo,
Vingron Martin,
Grummt Ingrid
Publication year - 2000
Publication title -
embo reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.584
H-Index - 184
eISSN - 1469-3178
pISSN - 1469-221X
DOI - 10.1093/embo-reports/kvd032
Subject(s) - biology , rna polymerase i , transcription (linguistics) , microbiology and biotechnology , ribosome , rna polymerase ii , ribosomal rna , rna polymerase iii , transcription factor , cycloheximide , rna , rna polymerase , genetics , protein biosynthesis , gene , promoter , gene expression , linguistics , philosophy
Cells carefully modulate the rate of rRNA transcription in order to prevent an overinvestment in ribosome synthesis under less favorable nutritional conditions. In mammals, growth‐dependent regulation of RNA polymerase I (Pol I) transcription is mediated by TIF‐IA, an essential initiation factor that is active in extracts from growing but not starved or cycloheximide‐treated mammalian cells. Here we report the molecular cloning and functional characterization of recombinant TIF‐IA, which turns out to be the mammalian homolog of the yeast factor Rrn3p. We demonstrate that TIF‐IA interacts with Pol I in the absence of template DNA, augments Pol I transcription in vivo and rescues transcription in extracts from growth‐arrested cells in vitro .