Enables DNA-binding transcription factor activity, RNA polymerase II-specific; RNA polymerase II cis-regulatory region sequence-specific DNA binding activity; and intronic transcription regulatory region sequence-specific DNA binding activity. Involved in negative regulation of transcription, DNA-templated; positive regulation of circadian rhythm; and positive regulation of transcription, DNA-templated. Acts upstream of or within several processes, including animal organ development; neurogenesis; and regulation of transcription by RNA polymerase II. Located in nucleus. Part of transcription regulator complex. Is expressed in several structures, including alimentary system; genitourinary system; nervous system; respiratory system; and sensory organ. Human ortholog(s) of this gene implicated in choreatic disease and thyroid gland papillary carcinoma. Orthologous to human NKX2-1 (NK2 homeobox 1). [provided by Alliance of Genome Resources, Apr 2022]