Plays a role in splicing of the U12-type introns (PubMed:29617656). Implicated also in removal of U2 introns positioned adjacent to a U12 intron (PubMed:29617656). Interacts with SF3B1 (PubMed:29617656). Interacts with ZCRB1 (PubMed:29617656). Highest expression levels are detected in the brain, and lower expression levels in other tissues like epididymis, testis, bone marrow or muscle (PubMed:29617656). In testis, expressed in both Sertoli and spermatogenic cell (PubMed:29617656). Expressed at the 2-cell stage, and at the morula and blastocyst stages. No visible phenotype, possibly because of the compensating effects of one or more of the other 3 paralogs (U2AF1, U2AF1L4, ZRSR2). Maternally imprinted. Active paternal allele is unmethylated whereas the inactive maternal allele is highly methylated.