Interaction between the RNA binding domains of Ser-Arg splicing factor 1 and U1-70K snRNP protein determines early spliceosome assembly
| Autor: | Suhyung Cho, Amy Hoang, Gourisankar Ghosh, Xiang-Yang Zhong, Xiang-Dong Fu, Rahul Sinha, Adrian R. Krainer |
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| Rok vydání: | 2011 |
| Předmět: |
Spliceosome
RNA Splicing Exonic splicing enhancer RNA-binding protein Biology Heterogeneous ribonucleoprotein particle Ribonucleoprotein U1 Small Nuclear SR protein RNA Precursors Humans snRNP Phosphorylation Binding Sites Multidisciplinary Serine-Arginine Splicing Factors fungi Intron Nuclear Proteins RNA-Binding Proteins Biological Sciences Molecular biology Cell biology RNA splicing Spliceosomes HeLa Cells Protein Binding |
| Zdroj: | Proceedings of the National Academy of Sciences. 108:8233-8238 |
| ISSN: | 1091-6490 0027-8424 |
| DOI: | 10.1073/pnas.1017700108 |
| Popis: | It has been widely accepted that the early spliceosome assembly begins with U1 small nuclear ribonucleoprotein (U1 snRNP) binding to the 5′ splice site (5′SS), which is assisted by the Ser/Arg (SR)-rich proteins in mammalian cells. In this process, the RS domain of SR proteins is thought to directly interact with the RS motif of U1-70K, which is subject to regulation by RS domain phosphorylation. Here we report that the early spliceosome assembly event is mediated by the RNA recognition domains (RRM) of serine/arginine-rich splicing factor 1 (SRSF1), which bridges the RRM of U1-70K to pre-mRNA by using the surface opposite to the RNA binding site. Specific mutation in the RRM of SRSF1 that disrupted the RRM–RRM interaction also inhibits the formation of spliceosomal E complex and splicing. We further demonstrate that the hypo-phosphorylated RS domain of SRSF1 interacts with its own RRM, thus competing with U1-70K binding, whereas the hyper-phosphorylated RS domain permits the formation of a ternary complex containing ESE, an SR protein, and U1 snRNP. Therefore, phosphorylation of the RS domain in SRSF1 appears to induce a key molecular switch from intra- to intermolecular interactions, suggesting a plausible mechanism for the documented requirement for the phosphorylation/dephosphorylation cycle during pre-mRNA splicing. |
| Databáze: | OpenAIRE |
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