Cloning, characterization, and genomic structure of the mouse Ikbkap gene

Our laboratory recently reported that mutations in the human I-kappaB kinas e-associated protein (IKBYAP) gene are responsible for familial dysautonomi a (FD). Interestingly, amino acid substitutions in the IKAP correlate with increased risk for childhood bronchial asthma. Here, we report the cloning and genomic characterization of the mouse Ikbkap gene, the homolog of human IKBKAP. Like its human counterpart, Ikbkap encodes a protein of 1332 amino acids with a molecular weight of approximately 150 kDa. The Ikbkap gene pr oduct, Ikap, contains 37 exons that span approximately 51 kb. The protein s hows 80% amino acid identity with human IKAP. It shows very high conservati on across species and is homologous to the yeast Elp1/Iki3p protein, which is a member of the Elongator complex. The Ikbkap gene maps to chromosome 4 in a region that is syntenic to human chromosome 9q31.3. Because no animal model of FD currently exists, cloning of the mouse Ikbkap gene is an import ant first step toward creating a mouse model for FD. In addition, cloning o f Ikbkap is crucial to the characterization of the putative mammalian Elong ator complex.