Enables mRNA 3'-UTR binding activity and sequence-specific mRNA binding activity. Involved in negative regulation of cold-induced thermogenesis and regulation of alternative mRNA splicing, via spliceosome. Acts upstream of or within mRNA splicing, via spliceosome and regulation of RNA metabolic process. Located in nucleus. Is expressed in several structures, including nervous system and retina. Orthologous to human NOVA1 (NOVA alternative splicing regulator 1). [provided by Alliance of Genome Resources, Apr 2022]