Neural expression and regulation of NSSRI proteins

Neural salient serine-/arginine-rich protein I (NSSRI) is a newly identified SR protein that regulates pre-mRNA splicing. In the present study, we demonstrated the neural specialization of NSSRI protein expression in humans and mice. Strong immunoreactive signals to NSSRI were observed in mouse cerebral neurons, cerebellar Purkinje cells, pyramidal neurons in CA1, CA2 and CA3 regions of the hippocampus and granule cells in the dentate gyrus. In primarily cultured mouse neural progenitor cells (NPCs), at the undifferentiated status, NSSRI transcripts were detected, but not the proteins. In comparison, in differentiated NPCs both NSSRI transcripts and proteins were expressed and significantly up-regulated. The results suggest that NSSRI is important in regulation of brain function and neural differentiation, possibly via regulating the neural-specific alternative splicing of genes.