TBP2 is a substitute for TBP in Xenopus oocyte transcription.
BMC Biol
; 7: 45, 2009 Aug 03.
Article
en En
| MEDLINE
| ID: mdl-19650908
BACKGROUND: TATA-box-binding protein 2 (TBP2/TRF3) is a vertebrate-specific paralog of TBP that shares with TBP a highly conserved carboxy-terminal domain and the ability to bind the TATA box. TBP2 is highly expressed in oocytes whereas TBP is more abundant in embryos. RESULTS: We find that TBP2 is proteolytically degraded upon meiotic maturation; after germinal vesicle breakdown relatively low levels of TBP2 expression persist. Furthermore, TBP2 localizes to the transcriptionally active loops of lampbrush chromosomes and is recruited to a number of injected promoters in oocyte nuclei. Using an altered binding specificity mutant reporter system we show that TBP2 promotes RNA polymerase II transcription in vivo. Intriguingly, TBP, which in oocytes is undetectable at the protein level, can functionally replace TBP2 when ectopically expressed in oocytes, showing that switching of initiation factors can be driven by changes in their expression. Proteolytic degradation of TBP2 is not required for repression of transcription during meiotic maturation, suggesting a redundant role in this repression or a role in initiation factor switching between oocytes and embryos. CONCLUSION: The expression and transcriptional activity of TBP2 in oocytes show that TBP2 is the predominant initiation factor in oocytes, which is substituted by TBP on a subset of promoters in embryos as a result of proteolytic degradation of TBP2 during meiotic maturation.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Oocitos
/
Transcripción Genética
/
Ciclo Celular
/
TATA Box
/
Proteínas de Xenopus
/
Proteína de Unión a TATA-Box
Tipo de estudio:
Prognostic_studies
Límite:
Animals
Idioma:
En
Revista:
BMC Biol
Asunto de la revista:
BIOLOGIA
Año:
2009
Tipo del documento:
Article
País de afiliación:
Países Bajos
Pais de publicación:
Reino Unido