Integral Membrane Protein 2A (ITM2A)

The full-length E25A cDNA was predicted to encode a type II integral membrane protein of 263 amino acid residues. In situ hybridization showed that E25A is expressed in the outer perichondrial rim of the postnatal mandibular condyle, which contains the proliferating progenitor cells, but not in the deeper layers of the condyle containing the more differentiated chondroblasts and chondrocytes. Strong in situ hybridization signals were also detected on bone trabeculae of mature bone, in tooth germs, and in hair follicles. Northern blot analysis showed strong expression in osteogenic tissues, such as neonatal mouse calvaria, paws, and tail, and in skin. Homology searches of DNA databanks showed that E25A belongs to a novel multigene family, containing at least 3 members in both man and mouse.