LldI, a Plasmid-Encoded Type I Restriction and Modification System in Lactococcus Lactis

Abstract

A plasmid-encoded type I restriction and modification (R-M) system, designated LldI, was identified in Lactococcus lactis biovar diacetylactis LD10–1. LldI consists of three genes encoding endonuclease, methylase and specificity subunits, respectively. RT-PCR analysis revealed that the three genes are co-transcribed as a polycistronic mRNA in L. lactis. The specificity subu-nit of LldI differs significantly in the target recognition domains from those of other type I R-M systems, suggesting that LldI confers a novel specificity in L. lactis

Key Words:

• type I R-M system
• plasmid pND861
• Lactococcus lactis