Localization and Characterization of the Human ADP-Ribosylation Factor 5 (ARF5) Gene

ADP-ribosylation factor 5 (ARF5) is a member of the ARF gene family. The ARF proteins stimulate thein vitroADP-ribosyltransferase activity of cholera toxin and appear to play a role in vesicular traffickingin vivo.We have mapped ARF5, one of the six known mammalian ARF genes, to a well-defined yeast artificial chromosome contig on human chromosome 7q31.3. In addition, we have isolated and sequenced an ∼3.2-kb genomic segment that contains the entire ARF5 coding region, revealing the complete intron–exon structure of the gene. With six coding exons and five introns, the genomic structure of ARF5 is unique among the mammalian ARF genes and provides insight about the evolutionary history of this ancient gene family.