cDNA Cloning and Chromosomal Localization of the Genes Encoding the α- and β-Subunits of Human Rab Geranylgeranyl Transferase: The 3′ End of the α-Subunit Gene Overlaps with the Transglutaminase 1 Gene Promoter ☆

Abstract We have isolated and sequenced the complete coding sequences of the human genes for the α- and β-subunits of Rab geranylgeranyl transferase (Rab GGTase). The α- and β-subunit genes code for proteins of 567 and 331 amino acids, respectively, showing 91 and 95% amino acid identity to their rat counterparts. We employed fluorescence in situ hybridization to map the β-subunit gene to human chromosome 1p31. The α-subunit gene could be assigned to 14q11.2, less than 2 kb upstream of the transcription initiation site of the gene for transglutaminase 1 (TGM1). The two genes are arranged in tandem in a head-to-tail orientation. The short intergenic sequence between the two loci contains several promoter elements that are involved in the induction of TGM1 gene expression in squamous cells. These results suggest that cis -acting factors for cell-type-specific transcription of one gene are located within the transcribed region of a functionally unrelated gene.