Histone methyltransferase. Specifically methylates ‘Lys-4’ of histone H3, inducing di- and tri-methylation, but not monomethylation (PubMed:15235609, PubMed:22419068). Also methylates ‘Lys-5′ of histone H4 (PubMed:22419068). Plays an important role in transcriptional activation as a member of an RNA polymerase complex (PubMed:15235609). Binds DNA containing 5′-CCCTCC-3′ or 5′-GAGGGG-3’ sequences (PubMed:15235609).