Characterization of the genes coding for the<i>Eco</i>RV restriction and modification system of<i>Escherichia coli</i>

TLDR

The study proposes and discusses possible translational regulation mechanisms for the Eco RV endonuclease gene. The authors mapped the positions of the Eco RV endonuclease and methylase genes using overlapping deletions created by Bal31 resection. A 6.2‑kb plasmid pLB1 containing only the Eco RV genes was isolated, sequenced, and shown to have divergently transcribed endonuclease and methylase genes from a 310‑bp promoter region, with a 3‑kb subclone inserted into pBR322.

Abstract

A plasmid encoding the recently described Eco RV restriction and modification system has been isolated and characterized. This plasmid, pLB1 , is 6.2 kb long and carries only the Eco RV genes. A subclone of 3 kb has been inserted in pBR322. The relative positions of the endonuclease and the methylase genes were determined by the construction of a set of overlapping deletions generated by Bal31 resection. The DNA sequence of a 2.2 kb fragment containing the two genes was determined. The two genes are transcribed divergently from a 310 bp region and the assignment of the coding region has been confirmed by direct aminoacid sequence analysis. Possible mechanisms of regulation of the endonuclease gene expression at the translational level are proposed and discussed.