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Composition and processing activity of a semi-recombinant holo U7 snRNP
Katarzyna Bucholc1,2, Wei Shen Aik3, Xiao-Cui Yang1
1Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
Nucleic Acids Research
|December 11, 2019
Summary
Researchers reconstituted the U7 small nuclear ribonucleoprotein (snRNP) complex from recombinant parts. This functional U7 snRNP accurately processes histone pre-mRNAs, offering new insights into gene regulation.
Area of Science:
- Molecular Biology
- RNA Processing
- Gene Expression
Background:
- Replication-dependent histone pre-mRNAs require 3' end cleavage by the U7 small nuclear ribonucleoprotein (snRNP) complex.
- The U7 snRNP comprises U7 small nuclear RNA (snRNA) and specific Lsm proteins (Lsm10, Lsm11) that replace spliceosomal Sm proteins.
- Lsm11 protein interacts with FLASH, recruiting CPSF73 endonuclease and other factors to form the active holo U7 snRNP.
Purpose of the Study:
- To reconstitute the holo U7 snRNP complex from recombinant components.
- To analyze the structural and functional properties of the reconstituted U7 snRNP.
- To investigate the role of U7 snRNP components in histone pre-mRNA 3' end processing.
Main Methods:
- Assembly of core U7 snRNP bound to FLASH using recombinant proteins.
- Electron microscopy to analyze the structure of the reconstituted complex.
- In vitro processing assays using reconstituted U7 snRNP and nuclear extracts for histone pre-mRNA cleavage.
Main Results:
- Semi-recombinant holo U7 snRNP was successfully assembled and shown to possess identical composition and function to endogenous U7 snRNP.
- The reconstituted U7 snRNP accurately cleaved histone pre-mRNAs in vitro.
- The U7-specific Sm ring assembled efficiently in vitro, but engineered U7 snRNP showed impaired function.
Conclusions:
- The study successfully reconstituted a functional holo U7 snRNP complex in vitro.
- This reconstituted system accurately processes histone pre-mRNAs, validating its utility for mechanistic studies.
- The findings provide a platform for dissecting the roles of specific U7 snRNP and U7 snRNA elements in 3' end processing.
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