NOVEL INSERTION SEQUENCE-LIKE ELEMENT IS982 IN LACTOCOCCI

A novel insertion sequence-like (IS) element, designated IS982, was fo und on the lactose plasmid, pSK11L, from Lactococcus lactis subsp. cre moris SK11 and was located between the origin of replication and the o ligopeptide transport gene cluster. The 1003-base pair (bp) IS982 was flanked by 18-bp perfect inverted repeats. IS982 contained an open rea ding frame encoding a putative transposase of 296 amino acids. An almo st identical IS-like element (99% DNA sequence identity) was cloned an d partially sequenced from the chromosome of Lactococcus lactis subsp. cremoris Wg2 with 17-bp perfect inverted repeats. Southern analysis i ndicated that in 12 lactococcal strains examined, IS982 was present wi th copy numbers ranging from 1 to at least 20. IS982 displayed sequenc e homology to the putative IS element RSBst-alpha from Bacillus stearo thermophilus CU21. IS982 and RSBst-alpha were not related to other kno wn insertion sequences and may represent a new family of IS elements. (C) 1995 Academic Press. Inc.