MOLECULAR-CLONING OF A RHO FAMILY GENE OF ENTAMOEBA-HISTOLYTICA

An Entamoeba histolytica gene (Eh rho1) was cloned that encodes a putative low-molecular-mass GTP-binding protein, most similar to the ras homologue rho. The Eh rho1 open reading frame was 208 amino acids long and encoded a 23-kDa protein similar to Saccharomyces cerevisiae RHO1-RHO4 and CDC42 and human rhoA, rac1, and G25K gene products. This similarity was greatest at the NH2 terminus of Eh rho1 where two GTP-binding sites and a possible effector site were conserved. A cysteine residue at the COOH terminus of Eh rho1 was followed by eight hydrophobic amino acids rather than the three hydrophobic amino acids present in other ras family proteins.