7B0Y

Structure of a transcribing RNA polymerase II-U1 snRNP complex

Summary for 7B0Y

• Entry DOI: 10.2210/pdb7b0y/pdb
• Related: 7B0Y
• EMDB information: 11972
• Descriptor: DNA-directed RNA polymerase II subunit RPB1, DNA-directed RNA polymerases I, II, and III subunit RPABC5, DNA-directed RNA polymerase II subunit RPB11-a, ... (27 entities in total)
• Functional Keywords: transcription, splicing, co-transcriptional spliceosome assembly
• Biological source: Sus scrofa domesticus; More
• Total number of polymer chains: 25
• Total formula weight: 823570.47

Authors

Zhang, S.,Aibara, S.,Vos, S.M.,Agafonov, D.E.,Luehrmann, R.,Cramer, P. (deposition date: 2020-11-23, release date: 2021-01-13, Last modification date: 2024-05-01)

Primary citation

Zhang, S.,Aibara, S.,Vos, S.M.,Agafonov, D.E.,Luhrmann, R.,Cramer, P.
Structure of a transcribing RNA polymerase II-U1 snRNP complex.
Science, 371:305-309, 2021

PubMed Abstract: To initiate cotranscriptional splicing, RNA polymerase II (Pol II) recruits the U1 small nuclear ribonucleoprotein particle (U1 snRNP) to nascent precursor messenger RNA (pre-mRNA). Here, we report the cryo-electron microscopy structure of a mammalian transcribing Pol II-U1 snRNP complex. The structure reveals that Pol II and U1 snRNP interact directly. This interaction positions the pre-mRNA 5' splice site near the RNA exit site of Pol II. Extension of pre-mRNA retains the 5' splice site, leading to the formation of a "growing intron loop." Loop formation may facilitate scanning of nascent pre-mRNA for the 3' splice site, functional pairing of distant intron ends, and prespliceosome assembly. Our results provide a starting point for a mechanistic analysis of cotranscriptional spliceosome assembly and the biogenesis of mRNA isoforms by alternative splicing.

PubMed: 33446560
DOI: 10.1126/science.abf1870

Experimental method

ELECTRON MICROSCOPY (3.6 Å)