RNA-binding protein that regulates alternative splicing events by binding to 5'-UGCAUGU-3' elements. Prevents binding of U2AF2 to the 3'-splice site. Regulates alternative splicing of tissue-specific exons and of differentially spliced exons during erythropoiesis. Binds to the C-terminus of ATXN2. Predominantly nuclear. Detected in brain (at protein level). Detected in heart, brain, neurons, skeletal muscle and embryo.