Expression analysis and chromosomal assignment of the human SFRS5/SRp40 gene

Alternative splicing plays a major role in the regulation of gene expression. SFRS5/SRp40 is a member of the serine/arginine (SR) protein family of regulators of alternative pre-mRNA splicing. We cloned the human SFRS5 cDNA and observed two major SFRS5 transcripts, an approximately 1.8-kb short form and an approximately 3.3-kb long form, in both human and rat tissues. Both transcripts were detected in all human tissues examined, but there were notable tissue-specific differences in their relative abundance, the short form being most abundant in retina. Affinity-purified SFRS5 antisera recognized a single 40-kDa polypeptide in human and mouse retinal lysates. The abundant retinal expression of SFRS5 was not restricted to any specific cell type, since immunofluorescent labeling of human retinal sections identified the SFRS5 protein in nuclei of all three nuclear layers of the retina. The human SFRS5 gene was localized to human chromosome 14q24 by fluorescence in situ hybridization and PCR analysis of a human/hamster somatic cell hybrid panel.