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Golgi localization of Syne-1
Lisa Lucio Gough1, Jun Fan, Stephen Chu
1Department of Cell Biology and Human Anatomy, University of California, Davis, 95616, USA.
Molecular Biology of the Cell
|June 17, 2003
Summary
Researchers identified Syne-1, a novel spectrin-like protein, localizing to the Golgi apparatus. This protein impacts Golgi structure and may link the Golgi and nuclear envelope during muscle development.
Area of Science:
- Cell Biology
- Molecular Biology
- Genetics
Background:
- Previously identified a Golgi-localized spectrin isoform using antibodies to erythrocyte spectrin beta-subunit.
- Spectrin family members, like Nesprin-1beta, are known to associate with the nuclear envelope and bind acetylcholine receptors.
Purpose of the Study:
- To characterize a novel spectrin-like protein identified in Madin-Darby bovine kidney (MDBK) cells.
- To determine the function and localization of this protein, named Syne-1.
Main Methods:
- Screened a lambda gt11 expression library to isolate a partial cDNA.
- Performed BLAST searches and compared sequences with the human genome database.
- Expressed epitope-tagged Syne-1 fragments in MDBK and COS cells.
- Utilized immunofluorescence microscopy with various antibodies.
Main Results:
- Isolated a 5-kb partial cDNA encoding a 1697-amino acid polypeptide with 37% homology to spectrin.
- Identified this cDNA as a central portion of the Syne-1 gene, a large gene (approx. 500 kb) encoding a 25-kb transcript and an 8406-amino acid polypeptide.
- Demonstrated Golgi localization of Syne-1, identifying two distinct Golgi binding sites.
- Showed that a Syne-1 Golgi binding domain acts as a dominant-negative inhibitor, causing Golgi collapse near the centrosome in transfected cells.
Conclusions:
- The Syne-1 gene is expressed in multiple forms with dual localization at the Golgi and nuclear envelope.
- Syne-1 is multifunctional and may play a role in linking the Golgi and nuclear envelope during muscle differentiation.