Enables RNA binding activity. Involved in positive regulation of RNA splicing. Located in nucleus. Is expressed in diaphragm; heart; limb segment; skeletal musculature; and tail paraxial mesenchyme. Used to study atrial fibrillation and dilated cardiomyopathy 1DD. Human ortholog(s) of this gene implicated in dilated cardiomyopathy 1DD. Orthologous to human RBM20 (RNA binding motif protein 20). [provided by Alliance of Genome Resources, Apr 2022]