Splicing Factor 4 (SF4)

SF4 is a member of the SURP family of splicing factors. By EST database searching and genomic sequence analysis, Sampson and Hewitt (2003) identified 2 related members of the SURP family, which they called SF4 and SFRS14. SF4 encodes a deduced 645-amino acid protein with an estimated molecular mass of 72.5 kD. Both SF4 and SFRS14 contain 2 SURP motifs and a single G-patch domain in their C termini. Sampson and Hewitt (2003) also cloned the mouse orthologs; the mouse Sf4 protein shares an identical domain organization and 89% sequence identity with its human counterpart. Northern blot analysis detected expression of an approximately 2.1-kb SF4 transcript in all human fetal and adult tissues tested, with the exception of adult liver. The highest expression was detected in testis.