Pre-B-Cell Leukemia Homeobox Protein 2 (PBX2)

PBX2 encodes a ubiquitously expressed member of the TALE/PBX homeobox family. It was identified by its similarity to a homeobox gene which is involved in t(1;19) translocation in acute pre-B-cell leukemias. This protein is a transcriptional activator which binds to the TLX1 promoter. The gene is located within the major histocompatibility complex (MHC) on chromosome 6. The predicted PBX2 and PBX3 proteins were 92 and 94% identical to PBX1 over a large region of 266 amino acids within and flanking their homeodomains, but all 3 proteins diverged significantly near their amino and carboxy termini. Like PBX1 RNA, PBX3 RNA is alternatively spliced to yield 2 translation products with different carboxy termini, a feature not observed for PBX2.