Splicing at the phase-separated nuclear speckle interface: a model.
1Computer Science Department, Courant Institute of Mathematical Sciences, New York University, New York, NY, USA.
Nucleic Acids Research
|December 18, 2020
Summary
Phase-separated membraneless bodies spatially organize RNA splicing at their interfaces. This model explains how exon and intron binding by proteins positions splice sites for efficient splicing reactions.
Area of Science:
- Molecular Biology
- Cell Biology
- Biochemistry
Background:
- Membraneless bodies form through liquid-phase separation, crucial for nucleic acid biology.
- Current models emphasize protein compartmentalization, overlooking other phase separation properties.
- The functional roles of phase-separated body interfaces in organizing biochemical reactions are under-explored.
Purpose of the Study:
- To propose a novel model for the nuclear speckle's function in RNA splicing.
- To investigate the role of phase-separated body interfaces in spatially organizing biochemical reactions.
- To explain the complex logic of RNA splicing through sequence-dependent RNA positioning.
Main Methods:
- Developing a theoretical model for nuclear speckle function.
- Analyzing the proposed binding interactions of SR proteins and hnRNP proteins with exons and introns, respectively.
- Correlating RNA positioning at nuclear speckle interfaces with spliceosome accessibility.
Main Results:
- Exons are sequestered into nuclear speckles via SR proteins, while introns are excluded by hnRNP proteins.
- This differential binding positions splice sites at exon-intron boundaries at nuclear speckle interfaces.
- Interface localization enhances splice site accessibility to spliceosomes, facilitating splicing.
Conclusions:
- Phase-separated membraneless body interfaces can spatially organize biochemical reactions, exemplified by RNA splicing.
- The proposed model explains key aspects of splicing, including factor duality and motif position dependence.
- This interface-centric mechanism offers a new perspective on membraneless body function in nucleic acid biology.
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