Molecular cloning and characterization of gene for Golgi-localized syntaphilin-related protein on human chromosome 8q23

Abstract

Loci for several human genetic diseases including glaucoma have been mapped to q23 region on chromosome 8. We carried out homology search analysis of the genomic sequence of a bacterial artificial chromosome (BAC) clone, KB1590E11, on 8q23 region, and mapped a previously described cDNA, KIAA1472, to this BAC clone. In this study, we determined the complete genomic structure of the KIAA1472 gene and its expression in various tissues and cell lines. Four mRNA species (types 1a, 1b, 1c, and 2) were produced from this gene by use of alternative transcription start sites and alternative-splicing events. These mRNAs were expressed in various tissues, except for type 1a, which was found only in the brain. Further, type 1 mRNA could be translated into two protein isoforms with different N-terminal sequences; and type 2 mRNA, into another type of isoform. All three of these KIAA1472 gene products were localized in Golgi apparatus and contained a C-terminal hydrophobic segment characteristic of a transmembrane domain, thus indicating them to be Golgi membrane-bound proteins. Furthermore, these proteins were homologous to syntaphilin, a molecule involved in guiding vesicular transport. These results indicate that KIAA1472 gene products may play an important role in vesicular traffic in various tissues including the brain.