Myeloid/Lymphoid Or Mixed Lineage Leukemia 5 (MLL5)

MLL5 shares 38% amino acid identity with MLL, but it lacks the A-T hooks and MT homology domains found in MLL. Northern blot analysis detected a 6.5-kb transcript in all hematopoietic tissues examined.

MLL5 expression was also detected in all tissues analyzed on RNA tissue arrays, with the highest levels in fetal thymus and kidney and in adult hematopoietic tissues, jejunum, and cerebellum.MLL5 was biochemically identified in a GlcNAcylation-dependent multisubunit complex associating with nuclear retinoic acid receptor RAR-alpha (RARA), serving as a mono- and dimethyl transferase to H3K4. GlcNAcylation at thr440 in the MLL5 SET domain evoked its H3K4 HKMT activity and coactivated RAR-alpha in target gene promoters.