SFRS1, also named as ASF, SF2, SF2P33, SFRS1 and ASF-1, belongs to the splicing factor SR family. It plays a role in preventing exon skipping, ensuring the accuracy of splicing and regulating alternative splicing. SFRS1 interacts with other spliceosomal components, via the RS domains, to form a bridge between the 5'- and 3'-splice site binding components, U1 snRNP and U2AF. Isoform ASF-2 and isoform ASF-3 act as splicing repressors. This antibody can recognize all the 3 isoforms(28kd,33kd and 22kd) of SFRS1.