Enables DNA-binding transcription factor activity. Involved in activation of cysteine-type endopeptidase activity involved in apoptotic process and defense response to other organism. Acts upstream of or within several processes, including cell surface receptor signaling pathway; negative regulation of macrophage fusion; and response to exogenous dsRNA. Located in cytoplasm and nucleus. Is expressed in several structures, including alimentary system; central nervous system; genitourinary system; hemolymphoid system gland; and skeletal musculature. Used to study breast cancer and severe acute respiratory syndrome. Human ortholog(s) of this gene implicated in breast carcinoma; immunodeficiency 31A; immunodeficiency 31B; immunodeficiency 31C; and prostate adenocarcinoma. Orthologous to human STAT1 (signal transducer and activator of transcription 1). [provided by Alliance of Genome Resources, Apr 2022]