SRp54 (SFRS11), a Regulator for tau Exon 10 Alternative Splicing Identified by an Expression Cloning Strategy

Abstract

The tau gene encodes a microtubule-associated protein that is critical for neuronal survival and function. Splicing defects in the human tau gene lead to frontotemporal dementia with Parkinsonism linked to chromosome 17 (FTDP-17), an autosomal dominant neurodegenerative disorder. Genetic mutations associated with FTDP-17 often affect tau exon 10 alternative splicing. To investigate mechanisms regulating tau exon 10 alternative splicing, we have developed a green fluorescent protein reporter for tau exon 10 skipping and an expression cloning strategy to identify splicing regulators. A role for SRp54 (also named SFRS11) as a tau exon 10 splicing repressor has been uncovered using this strategy. The overexpression of SRp54 suppresses tau exon 10 inclusion. RNA interference-mediated knock-down of SRp54 increases exon 10 inclusion. SRp54 interacts with a purine-rich element in exon 10 and antagonizes Tra2β, an SR-domain-containing protein that enhances exon 10 inclusion. Deletion of this exonic element eliminates the activity of SRp54 in suppressing exon 10 inclusion. Our data support a role of SRp54 in regulating tau exon 10 splicing. These experiments also establish a generally useful approach for identifying trans-acting regulators of alternative splicing by expression cloning.

We thank N. Chaudary for generously providing the antibody against SRp54, Z. H. Jiang for help in the initial phase of the work, and Bill Nash for excellent technical assistance. We are grateful to members of the Wu laboratory for helpful discussions and/or critical reading of the manuscript.

This work was supported by grants from NIH (AG17518, GM07967, and EY014576), The Society for Progressive Supranuclear Palsy, the Muscular Dystrophy Association (J.Y.W.), and by a Scholar award from the Leukemia Society of America (J.Y.W.).