cDNA cloning and expression of an Arabidopsis GTP-binding protein of the ARF family

A cDNA clone encoding a small GTP-binding protein, the ADP-ribosylation factor (ARF) was isolated from a cDNA library of Arabidopsis thaliana cultured cells. The predicted amino acid sequence was highly homologous to the known yeast, bovine and human ARF sequences. Southern analysis of Arabidopsis genomic DNA suggested the existence of at least two copies of ARF genes. The level of ARF mRNA was found to be nearly constant during all cell growth stages in suspension cultures.