SF4 and SFRS14, two related putative splicing factors on human chromosome 19p13.11

The splicing of nascent mRNA precursors is an essential step for the expression of all intron-containing eukaryotic genes. Removal of intron sequences from nascent transcripts is mediated by the spliceosome, a large multicomponent complex. We describe here the identification of two genes encoding related, putative splicing factors on human chromosome 19p13.11, SF4 (splicing factor 4) and SFRS14 (splicing factor arginine/serine-rich 14). Both genes encode proteins containing a SURP motif; this domain is found in several splicing proteins including Drosophila alternative splicing regulator, suppressor-of-white-apricot (SWAP) and the yeast splicing factor, prp21p. In addition, SF4 and SFRS14 contain a G-patch domain at their C-termini, a motif present in a large number of eukaryotic RNA-binding proteins. SFRS14 also contains an N-terminal region that is rich in arginine/serine residues, suggesting SFRS14 is a novel member of the SR-related family of pre-mRNA processing factors. We have also identified the mouse orthologues of SF4 and SFRS14, based on conserved domain organization and high sequence similarity. Interestingly, SFRS14 undergoes alternative 3'-end processing events that are conserved between human and mouse, suggesting a functional significance.