37 exons, spanning over 100 kb

in a centromeric to telomeric direction; 13 and 15 kb; coding sequence: 11.9 kb

3969 amino acids; 431 KDa; contains from N-term to C-term 3 AT hooks homologous to high mobility group proteins HMGA1 and HMGA2, binding to the minor grove of DNA; 2 speckled nuclear localisation signals; 2 repression domains RD1 and RD2: RD1 or CXXC: cystein methyl transferase, binds CpG rich DNA, has a transcriptional repression activity; RD2 recruits histone desacetylases HDAC1 and 2; 3 plant homeodomains (cystein rich zinc finger domains, with homodimerization properties), 1 bromodomain (may bind acetylated histones), and 1 plant homeodomain; these domains may be involved in protein-protein interaction; a FYRN and a FRYC domain; a transactivation domain which binds CBP ; may acetylates H3 and H4 in the HOX area; a SET domain: methyltransferase; methyltates H3, including histones in the HOX area for allowing chromatin to be open to transcription. MLL is cleaved by taspase 1 into 2 proteins before entering the nucleus: a p300/320 N-term protein called MLL-N, and a p180 C-term protein, called MLL-C. The FYRN and a FRYC domains of native MLL associate MLL-N and MLL-C in a stable complex; they form a multiprotein complex with transcription factor TFIID.

wide; especially in: brain, kidney, thyroid; expressed in Taned B lymphocytes and myeloid cells

nuclear, in punctate spots

transcriptional regulatory factor; MLL may have yin-yang functions through actions of MLL-N and MLL-C (e.g. desacetylation/acetylation); MLL-N acts as a transcriptional repressor; MLL can be associated with more than 30 proteins, including the core components of the SWI/SNF chromatin remodeling complex and the transcription complex TFIID. MLL binds promotors of HOX genes through acetylation and methylation of histones. MLL is a major regulator of hematopoesis and embryonic development, through regulation of HOX genes expression regulation ( HOXA9 in particular).

trithorax (Drosophila), ALR (human), MLL2 (human)

MLL is implicated in at least 10 % of acute leukaemias (AL) of various types: acute lymphoblastic leukemias (ALL), acute non lymphocytic leukemias (AML), biphenotypic ALs, treatment related leukemias, infant leukemias; the prognosis is poor

spanning a 8 kb genomic region; between exons 5 to 11; highly variable on the partner, ranging from close to the NH2-term in MLLT1 (ENL), to near the COOH-term in MLLT3 (AF9)