Enables regulatory region RNA binding activity. Predicted to be involved in RNA splicing; myoblast differentiation; and regulation of alternative mRNA splicing, via spliceosome. Predicted to act upstream of or within several processes, including embryonic limb morphogenesis; mRNA splicing, via spliceosome; and skeletal muscle tissue development. Located in nucleus. Orthologous to human MBNL1 (muscleblind like splicing regulator 1). [provided by Alliance of Genome Resources, Apr 2022]