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Activation mutants in yeast RNA polymerase II subunit RPB3 provide evidence for a structurally conserved surface required for activation in eukaryotes and bacteria.

Authors :
Tan Q
Linask KL
Ebright RH
Woychik NA
Source :
Genes & development [Genes Dev] 2000 Feb 01; Vol. 14 (3), pp. 339-48.
Publication Year :
2000

Abstract

We have identified a mutant in RPB3, the third-largest subunit of yeast RNA polymerase II, that is defective in activator-dependent transcription, but not defective in activator-independent, basal transcription. The mutant contains two amino-acid substitutions, C92R and A159G, that are both required for pronounced defects in activator-dependent transcription. Synthetic enhancement of phenotypes of C92R and A159G, and of several other pairs of substitutions, is consistent with a functional relationship between residues 92-95 and 159-161. Homology modeling of RPB3 on the basis of the crystallographic structure of alphaNTD indicates that residues 92-95 and 159-162 are likely to be adjacent within the structure of RPB3. In addition, homology modeling indicates that the location of residues 159-162 within RPB3 corresponds to the location of an activation target within alphaNTD (the target of activating region 2 of catabolite activator protein, an activation target involved in a protein-protein interaction that facilitates isomerization of the RNA polymerase promoter closed complex to the RNA polymerase promoter open complex). The apparent finding of a conserved surface required for activation in eukaryotes and bacteria raises the possibility of conserved mechanisms of activation in eukaryotes and bacteria.

Details

Language :
English
ISSN :
0890-9369
Volume :
14
Issue :
3
Database :
MEDLINE
Journal :
Genes & development
Publication Type :
Academic Journal
Accession number :
10673505