A Region of a Sym Plasmid ofRhizobium leguminosarumbiovarphaseoliHas Similarity to Prokaryotic Insertion Sequences and to Eukaryotic Integrases

Abstract

Near thenodandnifgenes of the Sym plasmid pRP2JI ofRhizobium leguminosarumbiovarphaseoliare three open reading frames whose deduced polypeptide products have similarities to those of genes in bacterial insertion sequences. The similarity of one of these ORFs was significantly greater to that of the integrase region ofpolproteins of eukaryotic retroviruses and transposable elements in animals and plants than it was to the transposases of prokaryotic insertion sequences. In the noncoding region of the IS-like element, there was a sequence similar to that which had been identified close tonodgenes inAzorhizobium caulinodans.