Genomic Organization and Primary Characterization of miap -3: The Murine Homologue of Human X-Linked IAP

Abstract IAPs (inhibitor of apoptosis proteins) are a recently identified family of proteins that function in the cell death pathway to inhibit programmed cell death. We have earlier reported cloning of four human IAPs: NAIP, hiap -1, hiap -2, and xiap. To facilitate studies of these genes, we have undertaken the cloning of their murine homologues. We report here the cloning, mapping, and preliminary characterization (including cellular and tissue distribution profile) of the murine homologue of the human X-linked IAP ( xiap ). The mouse gene called miap -3 (for murine IAP-3; GenBank Accession No. nuc 1 U88990) has a coding region of 1.5 kb that encodes a protein of 55 kDa and has 87 and 94% homology with its human homologue at DNA and amino acid levels, respectively. Northern blot analysis reveals an 8-kb miap -3 transcript in all tissues examined to date. miap -3 is composed of six exons and five introns spanning approximately 20 kb. miap -3 has been assigned to the A3–A5 region of mouse chromosome X by FISH analysis.