Pre-B-Cell Leukemia Homeobox Protein 3 (PBX3)

Monica et al. (1991) mapped PBX3 to 9q33-q34 by in situ hybridization. Pilz et al. (1994) mapped the homologous gene to mouse chromosome 2. As part of a study of a triplication of several megabases occurring on chromosomes 1, 6, and 9, Katsanis et al. (1996) confirmed the presence of a PBX locus on chromosome 9q34.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. Chromosome in situ hybridization demonstrated that the PBX genes map to separate loci: PBX1, 1q23; PBX2, 3q22-q23; PBX3, 9q33-q34. It was subsequently determined that the PBX gene mapped to chromosome 3 was in fact a pseudogene (PBXP1).