High impact information on BAPX1

• Histone acetylation dependent allelic expression imbalance of BAPX1 in patients with the oculo-auriculo-vertebral spectrum [1].
• In a patient with OAVS and a chromosomal translocation t(4;8) we have found that the chromosome 4 breakpoint is 76.4 kb distal to the BAPX1 gene, which plays an essential role in craniofacial development [1].
• We did not detect any BAPX1 mutation in 105 patients, but observed a strong allelic expression imbalance (sAEI) in fibroblasts from five of 12 patients, but not in nine normal controls (Fisher's exact test, P=0.038). sAEI was de novo in one patient and inherited in two other patients [1].
• Gizzard formation and the role of Bapx1 [2].
• We show ectopic expression of Bapx1 in the proventriculus results in a gizzard-like morphology and inhibits the normal proventricular expression of Bmp4 and Wnt5a [2].

Biological context of BAPX1

• We report here the human BAPX1 sequence and its localization to chromosome region 4p16.1 and suggest BAPX1 as a candidate for disorders of skeletal development that might map to 4p16.1 [3].
• Expression of BAPX1 was evaluated during human embryonic development by RT-PCR analysis and by RNA in situ hybridization [4].
• Bapx1: an evolutionary conserved homologue of the Drosophila bagpipe homeobox gene is expressed in splanchnic mesoderm and the embryonic skeleton [5].
• Bapx1 continues to be expressed well into organogenesis in lateral plate mesoderm surrounding the mid- and hindgut, and in essentially all cartilaginous condensations which will subsequently undergo endochondral bone formation [5].

Anatomical context of BAPX1

• RNA in situ hybridization revealed that BAPX1 is predominantly expressed in mesenchymal condensations of the fetal limb and axial skeleton, and in lateral plate mesoderm giving rise to visceral muscle [4].
• RT-PCR analysis showed that BAPX1 is expressed in embryo tissues, particularly the limb, and at a lower level in an embryonic lung cell line [4].
• Bapx1 is first detectable in embryos just prior to axis rotation in lateral plate mesoderm (splanchnic mesoderm) adjacent to the endodermal lining of the prospective gut, and in the most newly formed somites in the region corresponding to the presclerotome, the precursor of the vertebrae [5].
• Thus, Bapx1 is one of the earliest developmental markers for the sclerotome portion of the somite and the gut mesentery [5].
• We suggest the role of Bapx1 is to regulate the expression of Bmp4 and Wnt5a to pattern the avian stomach [2].

Other interactions of BAPX1

• Molecular cloning, chromosomal mapping and developmental expression of BAPX1, a novel human homeobox-containing gene homologous to Drosophila bagpipe [4].

References