B-Cell CLL/Lymphoma 9 (Bcl9)

BCL9 is associated with B-cell acute lymphoblastic leukemia. It may be a target of translocation in B-cell malignancies with abnormalities of 1q21. Its function is unknown. The overexpression of BCL9 may be of pathogenic significance in B-cell malignancies.One allele showed novel sequences upstream of JH5 with no homology to either IGH or any other sequence in databases. Using a single-copy restriction fragment immediately 5-prime of JH5, PAC clones were isolated and mapped to 1q21 on normal metaphases by fluorescence in situ hybridization, confirming that this allele represented the translocation breakpoint. Sequence analysis of the 1q21 restriction fragment showed identity with an expressed sequenced tag, and this probe was therefore used to probe Northern blots.