Reevaluation of transcriptional regulation by TATA-binding protein oligomerization: predominance of monomers.
Biochemistry
; 39(10): 2633-8, 2000 Mar 14.
Article
en En
| MEDLINE
| ID: mdl-10704213
The TATA-binding protein (TBP) plays an important role in transcriptional initiation by all three nuclear RNA polymerases. TBP contains a conserved C-terminal domain (cTBP) that binds DNA. Crystallographic studies of cTBP (i.e., TBP without the N-terminal domain) from various species and molecular biology studies of cTBP and mixed cTBP/TBP species have led to the view that DNA binding by TBP is regulated by TBP dimerization. Using sedimentation equilibrium, we show that yeast cTBP forms dimers in solution at 5 degrees C with a dissociation constant of 7 +/- 1 microM. This observation of cTBP dimers in solution is in accord with the dimeric state observed in crystal structures of cTBP. In contrast, physiologically relevant, full-length yeast TBP is monomeric at 5 degrees C and forms dimers at 30 degrees C with a dissociation constant of 51 +/- 16 microM. This dissociation constant precludes formation of stable full-length TBP dimers at physiological concentrations. In addition, we tested for yeast TBP oligomerization in the presence of TBP-associated factors in the context of TFIID. No evidence for TBP oligomers was found using immunoprecipitation techniques from yeast whole-cell extracts. We conclude that yeast TBP is predominantly monomeric under physiological conditions, arguing against a role for TBP dimerization in the regulation of transcriptional initiation.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Polímeros
/
Factores de Transcripción
/
Transcripción Genética
/
TATA Box
/
Proteínas de Unión al ADN
Idioma:
En
Revista:
Biochemistry
Año:
2000
Tipo del documento:
Article
País de afiliación:
Estados Unidos
Pais de publicación:
Estados Unidos