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Updated: Sep 17, 2025

Artificial RNA Polymerase II Elongation Complexes for Dissecting Co-transcriptional RNA Processing Events
Published on: May 13, 2019
Structure of a transcribing Pol II-DSIF-SPT6-U1 snRNP complex
Luojia Zhang1, Christopher Batters1, Shintaro Aibara2
1MRC Laboratory of Molecular Biology, Cambridge, UK.
None:
In eukaryotic cells, splicing occurs predominantly co-transcriptionally, enhancing splicing efficiency and fidelity while introducing an additional layer of regulation over gene expression. RNA polymerase II (Pol II) facilitates co-transcriptional splicing by recruiting the U1 small nuclear ribonucleoprotein particle (U1 snRNP) to the nascent transcripts. Here, we report the cryo-electron microscopy structure of a transcribing Pol II-U1 snRNP complex with elongation factors DSIF and SPT6. In addition, our biochemical analysis reveals that the phosphorylated Pol II carboxyl-terminal domain and SPT6 interact directly with U1 snRNP proteins, facilitating its recruitment to the elongation complex. This multivalent interaction between U1 snRNP and the transcription elongation complex may both allow efficient spliceosome assembly and ensure transcription processivity.
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