Enables DNA-binding transcription activator activity, RNA polymerase II-specific. Involved in heterochromatin assembly; histone H3-K4 methylation; and oocyte growth. Acts upstream of or within in utero embryonic development and regulation of gene expression. Predicted to be located in nucleoplasm. Predicted to be part of MLL3/4 complex. Is expressed in several structures, including central nervous system; cranium; heart; integumental system; and sensory organ. Used to study Kabuki syndrome. Human ortholog(s) of this gene implicated in Kabuki syndrome and esophagus squamous cell carcinoma. Orthologous to human KMT2D (lysine methyltransferase 2D). [provided by Alliance of Genome Resources, Apr 2022]