Genomic organization, fine-mapping, and expression of the human islet-brain 1 (IB1) c-Jun-amino-terminal kinase interacting protein-1 (JIP-1) gene

Islet-brain 1 (IB1), a regulator of the pancreatic beta-cell function in th e rat, is homologous to JIP-1, a murine inhibitor of c-Jun amino-terminal k inase (JNK). Whether IB1 and JIP-1 are present in humans was not known. me report the sequence of the 2133-bp human IB1 cDNA, the expression, structur e, and fine-mapping of the human IB1 gene, and the characterization of an I B1 pseudogene. Human IB1 is 94% identical to rat IB1. The tissue-specific e xpression of IB1 in human is similar to that observed in rodent. The IB1 ge ne contains 12 exons and maps to chromosome 11 (11p11.2-p12), a region that is deleted in DEFECT-11 syndrome. Apart from an IB1 pseudogene on chromoso me 17 (17q21), no additional IB1-related gene was found in the human genome . Our data indicate that the sequence and expression pattern of IB1 are hig hly conserved between rodent and human and provide the necessary tools to i nvestigate whether IB1 is involved in human diseases. (C) 1999 Academic Pre ss.