Splicing factor SC35 promotes tau expression through stabilization of its mRNA.

Altered alternative splicing and accumulation of brain microtubule-associated protein tau are found in several tauopathies and are believed to lead to these neurodegenerative diseases. We found that in addition to promoting tau exon 10 inclusion, splicing factor SC35 also promoted tau expression in HEK-293T cells. The activity of SC35 in promotion of tau expression was limited to exon 10 containing tau isoforms. SC35 did not affect tau transcription, but stabilized tau mRNA by binding to the SC35-like element of exon 10. These results provide novel insight into the regulation of tau expression and a molecular mechanism of tauopathies.