Architecture of the multi-functional SAGA complex and the molecular mechanism of holding TBP.

Autor: Ben-Shem A; Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France.; Centre National de la Recherche Scientifique, UMR7104, Institut National de la Santé et de la Recherche Médicale, U1258, Université de Strasbourg, France.; Equipe labellisée Ligue Contre le Cancer, France., Papai G; Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France.; Centre National de la Recherche Scientifique, UMR7104, Institut National de la Santé et de la Recherche Médicale, U1258, Université de Strasbourg, France.; Equipe labellisée Ligue Contre le Cancer, France., Schultz P; Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France.; Centre National de la Recherche Scientifique, UMR7104, Institut National de la Santé et de la Recherche Médicale, U1258, Université de Strasbourg, France.; Equipe labellisée Ligue Contre le Cancer, France.
Jazyk: angličtina
Zdroj: The FEBS journal [FEBS J] 2021 May; Vol. 288 (10), pp. 3135-3147. Date of Electronic Publication: 2020 Sep 29.
DOI: 10.1111/febs.15563
Abstrakt: In eukaryotes, transcription of protein encoding genes is initiated by the controlled deposition of the TATA-box binding protein TBP onto gene promoters, followed by the ordered assembly of a pre-initiation complex. The SAGA co-activator is a 19-subunit complex that stimulates transcription by the action of two chromatin-modifying enzymatic modules, a transcription activator binding module, and by delivering TBP. Recent cryo electron microscopy structures of yeast SAGA with bound nucleosome or TBP reveal the architecture of the different functional domains of the co-activator. An octamer of histone fold domains is found at the core of SAGA. This octamer, which deviates considerably from the symmetrical analogue forming the nucleosome, establishes a peripheral site for TBP binding where steric hindrance represses interaction with spurious DNA. The structures point to a mechanism for TBP delivery and release from SAGA that requires TFIIA and whose efficiency correlates with the affinity of DNA to TBP. These results provide a structural basis for understanding specific TBP delivery onto gene promoters and the role played by SAGA in regulating gene expression. The properties of the TBP delivery machine harboured by SAGA are compared with the TBP loading device present in the TFIID complex and show multiple similitudes.
(© 2020 Federation of European Biochemical Societies.)
Databáze: MEDLINE
Externí odkaz: