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The mouse synemin gene encodes three intermediate filament proteins generated by alternative exon usage and different
Z G Xue1, Y Cheraud, V Brocheriou
1Biologie Moléculaire de la Différenciation, Department of Biochemistry, Université Denis Diderot Paris7, 75005 Paris, France. xue@ccr.jussieu.fr
Experimental Cell Research
|July 22, 2004
Summary
Mouse synemin gene produces three intermediate filament protein (IFP) isoforms via alternative splicing. These IFPs associate with muscle intermediate filaments, with distinct roles suggested by their differing structures and developmental timing.
Area of Science:
- Molecular Biology
- Cell Biology
- Biochemistry
Background:
- The human synemin gene encodes two intermediate filament proteins (IFPs).
- Understanding the diversity and function of synemin isoforms is crucial for muscle biology.
Purpose of the Study:
- To characterize the mouse synemin gene and its encoded protein isoforms.
- To investigate the in vivo association of synemin with muscle intermediate filaments.
- To elucidate the functional significance of different synemin isoforms.
Main Methods:
- Gene cloning and characterization of the mouse synemin gene.
- Analysis of alternative splicing to identify synemin isoforms.
- Immunological studies using wild-type and knockout mice (desmin- and vimentin-deficient).
- Microscopy to assess the organization of synemin fibrils in muscle.
Main Results:
- The mouse synemin gene encodes three distinct synemin isoforms (H, M, and L) through alternative splicing.
- Synemin L is a novel IFP with a unique tail sequence and open reading frame.
- H/M synemin isoforms are synthesized during embryonic development, while synemin L is found in adult muscles.
- Synemin H/M isoforms bind to desmin or vimentin in wild-type mouse muscle.
- Synemin association with muscle intermediate filaments in vivo was confirmed using knockout mice.
- Disruption of synemin fibril organization was observed in desmin- or vimentin-deficient muscles.
Conclusions:
- The mouse synemin gene generates functional diversity through alternative splicing, producing at least three IFPs.
- Synemin isoforms exhibit distinct developmental expression patterns and interact with desmin and vimentin.
- Synemin is integral to the organization of muscle intermediate filament networks, with isoform-specific roles suggested by their unique tail domains and expression profiles.
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