CLONING AND SEQUENCE OF ADP-RIBOSYLATION FACTOR-I (ARF1) FROM SCHIZOSACCHAROMYCES-POMBE

A gene encoding a homologue of the ADP-ribosylation factor (ARF) famil y of small GTP binding proteins was cloned from a Schizosaccharomyces pombe cDNA library by a functional screen of suppressors of sensitivit y to 3-aminotriazole in a gcn3 null strain of Saccharomyces cerevisiae . Two independent isolates each contained the full coding region of th e ARF1 gene. The encoded SpARF1 protein has a predicted molecular weig ht of 20618 and is 88% and 79% identical to human and S. cerevisiae AR F1 proteins, respectively. As independent isolates were obtained, this effect of the SpARF1 appears to be a real phenomenon, but cannot curr ently be easily understood within the context of the evidence for a ro le(s) for ARF proteins in the protein secretory pathway.