Rxivist logo

Structure of a transcribing RNA polymerase II-U1 snRNP complex

By Suyang Zhang, Shintaro Aibara, Seychelle M. Vos, Dmitry E Agafonov, Reinhard L├╝hrmann, Patrick Cramer

Posted 20 Oct 2020
bioRxiv DOI: 10.1101/2020.10.19.344200

To initiate co-transcriptional splicing, RNA polymerase II (Pol II) recruits U1 small nuclear ribonucleoprotein particle (U1 snRNP) to nascent pre-mRNA. Here we report the cryo-EM 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 5' splice site in pre-mRNA near the RNA exit site of Pol II. Extension of pre-mRNA retains the 5' splice site, leading to formation of an intron loop. Loop formation may facilitate scanning of the nascent pre-mRNA for the 3' splice site and enable prespliceosome assembly and functional pairing of distant intron ends. Our results provide a starting point for a mechanistic analysis of co-transcriptional splicing and the biogenesis of mRNA isoforms during alternative splicing. ### Competing Interest Statement The authors have declared no competing interest.

Download data

  • Downloaded 1,675 times
  • Download rankings, all-time:
    • Site-wide: 11,154
    • In molecular biology: 297
  • Year to date:
    • Site-wide: 11,905
  • Since beginning of last month:
    • Site-wide: 41,406

Altmetric data

Downloads over time

Distribution of downloads per paper, site-wide