Molecular cloning, chromosomal localization and expression pattern of porcine ADP-ribosylation factor(Arf) gene...

Adenosine diphosphate-ribosylation factors (Arfs) are a family of guanosine triphosphate-binding proteins involved in fundamental biological processes including secretion, endocytosis, phagocytosis, cytokinesis, cell adhesion and tumor cell invasion. We report here the molecular cloning, chromosome localization and expression analysis of porcine Arf1-6, of which Arf1-3 (Class I) have >93% similarity to each other and encode nearly similar proteins with 181 amino acids in length. Arf4 and Arf5 (Class II) are 78-81% homologous to Class I Arfs and both encode a protein of 180 amino acids, Arf6 (Class III) shows 64-68% homology to the other Arfs and encodes 175 amino acids. With radiation hybrid mapping, porcine Arf1-6 are assigned to chromosomes 14q21-q22, 12p14, 5p12-q11, 13q21.1, 18q24, 1q21-q27, respectively. Moreover, real-time quantitative RT-PCR assays show that porcine Arf1-6 are ubiquitous in all tissues examined, with the highest levels in the kidney and stomach and the lowest in muscle and the heart. This is the first report of molecular characterization of the Arf gene family in pigs.