AbiG, a genotypically novel abortive infection mechanism encoded by plasmid pCI750 of Lactococcus lactis subsp. cremoris UC653

Abstract

AbiG is an abortive infection (Abi) mechanism encoded by the conjugative plasmid pCI750 originally isolated from Lactococcus lactis subsp. cremoris UC653. Insensitivity conferred by this Abi manifested itself as complete resistance to φ712 (936 phage species) with only partial resistance to φc2 (c2 species). The mechanism did not inhibit phage DNA replication. The smallest subclone of pC1750 which expressed the Abi phenotype contained a 3.5-kb insert which encoded two potential open reading frames, abiGi (750 bp) and abiGii (1,194 bp) were separated by 2 bp and appeared to share a single promoter upstream of abiGi. These open reading frames showed no significant homology to sequences of either the DNA or protein databases; however, they did exhibit the typical low G+C content (29 and 27%, respectively) characteristic of lactococcal abi genes. In fact, the G+C content of a 7.0- kb fragment incorporating the abiG locus was 30%, which may suggest horizontal gene transfer from a species of low G+C content. In this context, it is notable that remnants of IS elements were observed throughout this 7.0- kb region.

Disciplines

Biology

DOI

10.1128/aem.62.9.3075-3082.1996

Full Publication Date

January 1996

Publication Details

Applied and Environmental Microbiology

Publisher

American Society for Microbiology

Resource Type

journal article

Access Rights

open access

License Condition

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

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