Enables DNA-binding transcription activator activity, RNA polymerase II-specific. Involved in several processes, including male gamete generation; negative regulation of transposition; and piRNA biosynthetic process. Located in nucleus. Is expressed in several structures, including central nervous system; early conceptus; genitourinary system; hemolymphoid system gland; and sensory organ. Orthologous to human MYBL1 (MYB proto-oncogene like 1). [provided by Alliance of Genome Resources, Apr 2022]