Histone methyltransferase. Preferentially dimethylates 'Lys- 4' and 'Lys-27' of histone H3 forming H3K4me2 and H3K27me2. H3 'Lys-4' methylation represents a specific tag for epigenetic transcriptional activation, while 'Lys-27' is a mark for transcriptional repression. . This is the function of ENSG00000147548 (NSD3, nuclear receptor binding SET domain protein 3).