Alternative titles; symbols
HGNC Approved Gene Symbol: PBX2
Cytogenetic location: 6p21.32 Genomic coordinates (GRCh38): 6:32,184,733-32,190,202 (from NCBI)
Monica et al. (1991) isolated 2 new homeobox genes, PBX2 and PBX3 (176312) on the basis of their extensive homology to PBX1 (176310). 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. Unlike PBX1, which is not expressed in lymphoid cell lines, expression of PBX2 and PBX3 was not restricted to particular states of differentiation or development, as mRNA transcripts of these genes were detected in most fetal and adult tissues and all cell lines. Like PBX1 RNA, PBX3 RNA is alternatively spliced to yield 2 translation products with different carboxy termini, a feature not observed for PBX2. Their extensive sequence similarity and widespread expression suggest a generalized, overlapping role for PBX proteins in most cell types. Differences in their amino and carboxy termini may modulate their activities, mediated in part by differential splicing and, for PBX1, protein fusion following t(1;19) chromosomal translocation.
Two distinct urokinase (PLAU; 191840) enhancer factor-3 (UEF3) complexes, which share a common 64-kD subunit but differ in having either a 50-kD or 40-kD subunit, recognize a TGACAG core DNA sequence. Berthelsen et al. (1998) identified PREP1 (PKNOX1; 602100) as the common 64-kD UEF3 subunit, PBX2 as the 50-kD subunit, and PBX1 isoform b (PBX1b) as the 40-kD subunit. Immunoprecipitation analysis confirmed that PREP1 also formed a complex with PBX1 isoform a (PBX1a), and interaction of PREP1 with its UEF3 partners was independent of DNA. Recombinant PREP1 bound to the TGACAG core sequence with low affinity. However, it bound with much higher affinity when it was cotranslated in vitro with either PBX1a, PBX1b, or PBX2, but not when it was mixed with its purified binding partners.
Aguado and Campbell (1995) characterized the genomic structure of the PBX2 gene on chromosome 6 and showed that it is split into 9 exons.
By in situ hybridization, Monica et al. (1991) mapped the PBX2 gene to chromosome 3q22-q23. However, by chromosome walks in the major histocompatibility complex (MHC) class III region near the junction with class II, Sugaya et al. (1994) identified a sequence thought to be that of PBX2. They confirmed its location on 6p21.3 by fluorescence in situ hybridization.
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 6p21.3.
Aguado, B., Campbell, R. D. The novel gene G17, located in the human major histocompatibility complex, encodes PBX2, a homeodomain-containing protein. Genomics 25: 650-659, 1995. [PubMed: 7759099] [Full Text: https://doi.org/10.1016/0888-7543(95)80007-9]
Berthelsen, J., Zappavigna, V., Mavilio, F., Blasi, F. Prep1, a novel functional partner of Pbx proteins. EMBO J. 17: 1423-1433, 1998. [PubMed: 9482739] [Full Text: https://doi.org/10.1093/emboj/17.5.1423]
Katsanis, N., Fitzgibbon, J., Fisher, E. M. C. Paralogy mapping: identification of a region in the human MHC triplicated onto human chromosomes 1 and 9 allows the prediction and isolation of novel PBX and NOTCH loci. Genomics 35: 101-108, 1996. [PubMed: 8661110] [Full Text: https://doi.org/10.1006/geno.1996.0328]
Monica, K., Galili, N., Nourse, J., Saltman, D., Cleary, M. L. PBX2 and PBX3, new homeobox genes with extensive homology to the human proto-oncogene PBX1. Molec. Cell. Biol. 11: 6149-6157, 1991. [PubMed: 1682799] [Full Text: https://doi.org/10.1128/mcb.11.12.6149-6157.1991]
Sugaya, K., Fukagawa, T., Matsumoto, K., Mita, K., Takahashi, E., Ando, A., Inoko, H., Ikemura, T. Three genes in the human MHC class III region near the junction with the class II: gene for receptor of advanced glycosylation end products, PBX2 homeobox gene and a Notch homolog, human counterpart of mouse mammary tumor gene int-3. Genomics 23: 408-419, 1994. [PubMed: 7835890] [Full Text: https://doi.org/10.1006/geno.1994.1517]