# Structure and function of spliceosome

> **NIH NIH R01** · UNIVERSITY OF COLORADO DENVER · 2021 · $429,654

## Abstract

Abstract
Pre-mRNA splicing is essential for gene expression in all eukaryotes and errors in splicing cause genetic
disorders and many other diseases. A thorough understanding of the molecular mechanisms of pre-mRNA
splicing has the potential to provide useful approaches for human disease therapy. The splicing of introns is
carried out through two transesterification reactions catalyzed by the spliceosome, a large RNA/protein
complex composed of five snRNPs (U1, U2, U4, U5, U6) and many non-snRNP related protein factors. The
spliceosome undergoes dramatic changes in a splicing cycle, generating the E, A, Pre-B, B, Bact, B*, C, C*, P,
and ILS complexes. High resolution cryoEM structures of A, pre-B, B, Bact, C, C*, P, and ILS complexes have
been determined in the last few years, generating intriguing hypotheses on the mechanism of splicing that
await rigorous testing through biochemical and/or genetic analyses. The cryoEM structure of the post-catalytic
P complex we determined at 3.3 Å resolution provided intriguing hypothesis on the importance of intronic
secondary structures in 3’ ss recognition. In this proposal, we will use genome-wide chemical and enzymatic
probing to test this hypothesis. The structure of the P complex also led to hypotheses on the structure and
function of DEAD-box helicase Prp22 in splicing, which we will test using a combination of biochemical and
genetic experiments. Furthermore, the cryoEM structure of the spliceosome E complex we just determined
suggested mechanism of exon definition and its conversion to intron definition, which we will test using
biochemical and structural approaches. The combination of genomic, biochemical, and structural approaches
used in this proposal has the potential to provide a complete mechanistic understanding of the entire splicing
cycle.

## Key facts

- **NIH application ID:** 10219306
- **Project number:** 5R01GM130673-03
- **Recipient organization:** UNIVERSITY OF COLORADO DENVER
- **Principal Investigator:** RUI ZHAO
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $429,654
- **Award type:** 5
- **Project period:** 2019-09-01 → 2023-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10219306

## Citation

> US National Institutes of Health, RePORTER application 10219306, Structure and function of spliceosome (5R01GM130673-03). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10219306. Licensed CC0.

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