Molecular cloning and characterization of two novel genes on chromosome 8p21.3.

Through large-scale sequencing of genomic DNA from human chromosome 8p22-p21.3 we have isolated two novel genes, designated GK1 and G5. Their predicted products showed no significant similarity to any known proteins in public databases. A comparison of GK1 cDNA sequences, which encode a 1270-amino-acid protein, with corresponding genomic DNA sequences revealed that this gene consists of 15 exons and spans an approximately 113-kb genomic region. Northern blot analysis revealed ubiquitous expression of 7.0- and 4.4-kb transcripts; in addition, we detected a 5.0-kb skeletal muscle-specific transcript and a 4.0-kb transcript specifically expressed in heart and pancreas. Computer and immunocytochemical analyses of a GK1 Green fluolesent protein (GFP) fused construct indicated that the gene product, which contains putative leucine-zipper domains, was likely to be a mitochondrial protein. The other novel gene, G5, expressed four transcripts (4.2, 2.2, 1.7, and 1.0-kb) ubiquitously; the longer three transcripts, which differed only in the 3'-non coding region, encoded identical 397-amino-acid peptides. The G5 gene consists of 14 exons and spans approximately 52 kb of genomic DNA; its deduced 397-amino acid product appears to contain coiled-coil domains and a proline-rich region, and to be located in cytoplasm.