Isolation of a cDNA encoding a novel GTP-binding protein of Arabidopsis thaliana

A cDNA encoding for a 68 kDa GTP-binding protein was isolated from Arabidopsis thaliana (aG68). This clone is a member of a gene family that codes for a class of large GTP-binding proteins. This includes the mammalian dynamin, yeast Vps1p and the vertebrate Mx proteins. The predicted amino acid sequence was found to have high sequence conservation in the N-terminal GTP-binding domain sharing 54% identity to yeast Vps1p, 56% amino acid identity to rat dynamin and 38% identity to the murine Mx1 protein. The northern analysis shows expression in root, leaf, stem and flower tissues, but in mature leaves at lower levels. Southern analysis indicates that it may be a member of a small gene family or the gene may contain an intron.