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-Structure paper
Title | Structure of a transcribing RNA polymerase II-U1 snRNP complex. |
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Journal, issue, pages | Science, Vol. 371, Issue 6526, Page 305-309, Year 2021 |
Publish date | Jan 15, 2021 |
![]() | Suyang Zhang / Shintaro Aibara / Seychelle M Vos / Dmitry E Agafonov / Reinhard Lührmann / Patrick Cramer / ![]() |
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 ...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. |
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Methods | EM (single particle) |
Resolution | 3.2 - 5.9 Å |
Structure data | EMDB-11972: Overall map of a transcribing RNA polymerase II-U1 snRNP complex with 145-nt RNA ![]() EMDB-11973: ![]() EMDB-11974: ![]() EMDB-11975: |
Chemicals | ![]() ChemComp-ZN: ![]() ChemComp-MG: |
Source |
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![]() | SPLICING / Transcription / co-transcriptional spliceosome assembly |