8GXS

PIC-Mediator in complex with +1 nucleosome (T40N) in H-binding state

This is a non-PDB format compatible entry.

Summary for 8GXS

• Entry DOI: 10.2210/pdb8gxs/pdb
• Related: 8GXQ
• EMDB information: 33867 33885 33886 34215 34255 34256 34257 34359 34360
• Descriptor: DNA (228-mer), Histone H3, DNA-directed RNA polymerase subunit, ... (80 entities in total)
• Functional Keywords: pic, mediator, transcription initiation, +1 nucleosome, transcription
• Biological source: Xenopus laevis (African clawed frog); More
• Total number of polymer chains: 87
• Total formula weight: 4274920.15

Authors

Chen, X.,Wang, X.,Liu, W.,Ren, Y.,Qu, X.,Li, J.,Yin, X. (deposition date: 2022-09-21, release date: 2022-11-02, Last modification date: 2024-11-06)

Primary citation

Chen, X.,Wang, X.,Liu, W.,Ren, Y.,Qu, X.,Li, J.,Yin, X.,Xu, Y.
Structures of +1 nucleosome-bound PIC-Mediator complex.
Science, 378:62-68, 2022

PubMed Abstract: RNA polymerase II-mediated eukaryotic transcription starts with the assembly of the preinitiation complex (PIC) on core promoters. The +1 nucleosome is well positioned about 40 base pairs downstream of the transcription start site (TSS) and is commonly known as a barrier of transcription. The +1 nucleosome-bound PIC-Mediator structures show that PIC-Mediator prefers binding to T40N nucleosome located 40 base pairs downstream of TSS and contacts T50N but not the T70N nucleosome. The nucleosome facilitates the organization of PIC-Mediator on the promoter by binding TFIIH subunit p52 and Mediator subunits MED19 and MED26 and may contribute to transcription initiation. PIC-Mediator exhibits multiple nucleosome-binding patterns, supporting a structural role of the +1 nucleosome in the coordination of PIC-Mediator assembly. Our study reveals the molecular mechanism of PIC-Mediator organization on chromatin and underscores the significance of the +1 nucleosome in regulating transcription initiation.

PubMed: 36201575
DOI: 10.1126/science.abn8131

Experimental method

ELECTRON MICROSCOPY (4.16 Å)