Enables RNA polymerase II-specific DNA-binding transcription factor binding activity and sequence-specific DNA binding activity. Involved in several processes, including determination of adult lifespan; positive regulation of RNA splicing; and response to starvation. Located in nucleus. Expressed in several structures, including excretory cell; hermaphrodite gonad; nervous system; pharyngeal-intestinal valve; and pharynx. Human ortholog(s) of this gene implicated in several diseases, including carcinoma (multiple); gastrointestinal system cancer (multiple); and lymphoma (multiple). Is an ortholog of human JUN (Jun proto-oncogene, AP-1 transcription factor subunit); JUNB (JunB proto-oncogene, AP-1 transcription factor subunit); and JUND (JunD proto-oncogene, AP-1 transcription factor subunit).