Proteomic identification of heterogeneous nuclear ribonucleoprotein L as a novel component of SLM/Sam68 Nuclear Bodies
<p>Abstract</p> <p>Background</p> <p>Active pre-mRNA splicing occurs co-transcriptionally, and takes place throughout the nucleoplasm of eukaryotic cells. Splicing decisions are controlled by networks of nuclear RNA-binding proteins and their target sequences, sometimes...
| Main Authors: | , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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BMC
2009-11-01
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| Series: | BMC Cell Biology |
| Online Access: | http://www.biomedcentral.com/1471-2121/10/82 |
| _version_ | 1818583940975296512 |
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| author | Bindereif Albrecht Clark Emma L Emami Kaveh Heiner Monika Bourgeois Cyril F Dalgliesh Caroline Rajan Prabhakar Stevenin James Robson Craig N Leung Hing Y Elliott David J |
| author_facet | Bindereif Albrecht Clark Emma L Emami Kaveh Heiner Monika Bourgeois Cyril F Dalgliesh Caroline Rajan Prabhakar Stevenin James Robson Craig N Leung Hing Y Elliott David J |
| author_sort | Bindereif Albrecht |
| collection | DOAJ |
| description | <p>Abstract</p> <p>Background</p> <p>Active pre-mRNA splicing occurs co-transcriptionally, and takes place throughout the nucleoplasm of eukaryotic cells. Splicing decisions are controlled by networks of nuclear RNA-binding proteins and their target sequences, sometimes in response to signalling pathways. Sam68 (Src-associated in mitosis 68 kDa) is the prototypic member of the STAR (Signal Transduction and Activation of RNA) family of RNA-binding proteins, which regulate splicing in response to signalling cascades. Nuclear Sam68 protein is concentrated within subnuclear organelles called SLM/Sam68 Nuclear Bodies (SNBs), which also contain some other splicing regulators, signalling components and nucleic acids.</p> <p>Results</p> <p>We used proteomics to search for the major interacting protein partners of nuclear Sam68. In addition to Sam68 itself and known Sam68-associated proteins (heterogeneous nuclear ribonucleoproteins hnRNP A1, A2/B1 and G), we identified hnRNP L as a novel Sam68-interacting protein partner. hnRNP L protein was predominantly present within small nuclear protein complexes approximating to the expected size of monomers and dimers, and was quantitatively associated with nucleic acids. hnRNP L spatially co-localised with Sam68 as a novel component of SNBs and was also observed within the general nucleoplasm. Localisation within SNBs was highly specific to hnRNP L and was not shared by the closely-related hnRNP LL protein, nor any of the other Sam68-interacting proteins we identified by proteomics. The interaction between Sam68 and hnRNP L proteins was observed in a cell line which exhibits low frequency of SNBs suggesting that this association also takes place outside SNBs. Although ectopic expression of hnRNP L and Sam68 proteins independently affected splicing of <it>CD44 </it>variable exon v5 and <it>TJP1 </it>exon 20 minigenes, these proteins did not, however, co-operate with each other in splicing regulation of these target exons.</p> <p>Conclusion</p> <p>Here we identify hnRNP L as a novel SNB component. We show that, compared with other identified Sam68-associated hnRNP proteins and hnRNP LL, this co-localisation within SNBs is specific to hnRNP L. Our data suggest that the novel Sam68-hnRNP L protein interaction may have a distinct role within SNBs.</p> |
| first_indexed | 2024-12-16T08:13:16Z |
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| issn | 1471-2121 |
| language | English |
| last_indexed | 2024-12-16T08:13:16Z |
| publishDate | 2009-11-01 |
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| spelling | doaj.art-8e1f9c25013d4dff9003170f317d49ca2022-12-21T22:38:19ZengBMCBMC Cell Biology1471-21212009-11-011018210.1186/1471-2121-10-82Proteomic identification of heterogeneous nuclear ribonucleoprotein L as a novel component of SLM/Sam68 Nuclear BodiesBindereif AlbrechtClark Emma LEmami KavehHeiner MonikaBourgeois Cyril FDalgliesh CarolineRajan PrabhakarStevenin JamesRobson Craig NLeung Hing YElliott David J<p>Abstract</p> <p>Background</p> <p>Active pre-mRNA splicing occurs co-transcriptionally, and takes place throughout the nucleoplasm of eukaryotic cells. Splicing decisions are controlled by networks of nuclear RNA-binding proteins and their target sequences, sometimes in response to signalling pathways. Sam68 (Src-associated in mitosis 68 kDa) is the prototypic member of the STAR (Signal Transduction and Activation of RNA) family of RNA-binding proteins, which regulate splicing in response to signalling cascades. Nuclear Sam68 protein is concentrated within subnuclear organelles called SLM/Sam68 Nuclear Bodies (SNBs), which also contain some other splicing regulators, signalling components and nucleic acids.</p> <p>Results</p> <p>We used proteomics to search for the major interacting protein partners of nuclear Sam68. In addition to Sam68 itself and known Sam68-associated proteins (heterogeneous nuclear ribonucleoproteins hnRNP A1, A2/B1 and G), we identified hnRNP L as a novel Sam68-interacting protein partner. hnRNP L protein was predominantly present within small nuclear protein complexes approximating to the expected size of monomers and dimers, and was quantitatively associated with nucleic acids. hnRNP L spatially co-localised with Sam68 as a novel component of SNBs and was also observed within the general nucleoplasm. Localisation within SNBs was highly specific to hnRNP L and was not shared by the closely-related hnRNP LL protein, nor any of the other Sam68-interacting proteins we identified by proteomics. The interaction between Sam68 and hnRNP L proteins was observed in a cell line which exhibits low frequency of SNBs suggesting that this association also takes place outside SNBs. Although ectopic expression of hnRNP L and Sam68 proteins independently affected splicing of <it>CD44 </it>variable exon v5 and <it>TJP1 </it>exon 20 minigenes, these proteins did not, however, co-operate with each other in splicing regulation of these target exons.</p> <p>Conclusion</p> <p>Here we identify hnRNP L as a novel SNB component. We show that, compared with other identified Sam68-associated hnRNP proteins and hnRNP LL, this co-localisation within SNBs is specific to hnRNP L. Our data suggest that the novel Sam68-hnRNP L protein interaction may have a distinct role within SNBs.</p>http://www.biomedcentral.com/1471-2121/10/82 |
| spellingShingle | Bindereif Albrecht Clark Emma L Emami Kaveh Heiner Monika Bourgeois Cyril F Dalgliesh Caroline Rajan Prabhakar Stevenin James Robson Craig N Leung Hing Y Elliott David J Proteomic identification of heterogeneous nuclear ribonucleoprotein L as a novel component of SLM/Sam68 Nuclear Bodies BMC Cell Biology |
| title | Proteomic identification of heterogeneous nuclear ribonucleoprotein L as a novel component of SLM/Sam68 Nuclear Bodies |
| title_full | Proteomic identification of heterogeneous nuclear ribonucleoprotein L as a novel component of SLM/Sam68 Nuclear Bodies |
| title_fullStr | Proteomic identification of heterogeneous nuclear ribonucleoprotein L as a novel component of SLM/Sam68 Nuclear Bodies |
| title_full_unstemmed | Proteomic identification of heterogeneous nuclear ribonucleoprotein L as a novel component of SLM/Sam68 Nuclear Bodies |
| title_short | Proteomic identification of heterogeneous nuclear ribonucleoprotein L as a novel component of SLM/Sam68 Nuclear Bodies |
| title_sort | proteomic identification of heterogeneous nuclear ribonucleoprotein l as a novel component of slm sam68 nuclear bodies |
| url | http://www.biomedcentral.com/1471-2121/10/82 |
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