The cloning, mapping and expression of a novel gene, BRL, related to the AF10 leukaemia gene

The MLL gene is reciprocally translocated with one of a number of different partner genes in a proportion of human acute leukaemias. The precise mecha nism of oncogenic transformation is unclear since most of the partner genes encode unrelated proteins, However, two partner genes, AF10 and AF17 are r elated through the presence of a cysteine rich region and a leucine zipper. The identification of other proteins with these structures will aid our un derstanding of their role in normal and leukaemic cells. We report the clon ing of a novel human gene (BRL) which encodes a protein containing a cystei ne rich region related to that of AF10 and AF17 and is overall most closely related to the previously known protein BR140, BRL maps to chromosome 22q1 3 and shows high levels of expression in testis and several cell lines. The deduced protein sequence also contains a bromodomain, four potential LXXLL motifs and four predicted nuclear localization signals. A monoclonal antib ody raised to a BRL peptide sequence confirmed its widespread expression as a 120 Kd protein and demonstrated localization to the nucleus within sperm atocytes.