Limb Bud And Heart Development Homolog (LBH)

The deduced 105-amino acid human and mouse proteins have a calculated molecular mass of 12 kD, and human LBH shares 90% amino acid identity with its mouse and bovine orthologs. The LBH proteins contain an N-terminal hydrophobic region, a putative nuclear localization signal, and a C-terminal acidic glutamate-rich domain. There are 2 predicted alpha helices that could act as protein-protein interaction interfaces. Immunohistochemical studies localized Lbh to the nucleus. Northern blot analysis of adult mouse tissues detected highest Lbh expression in the heart, followed by lung, spleen, brain, and kidney. Whole-mount in situ hybridization detected Lbh expression in embryonic bilateral heart primordia becoming more localized after heart tube fusion and looping, with highest expression in the right ventricle, atrioventricular canal, and sinus venosus.