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Functional analysis of the Enterococcus faecalis plasmid pAD1‐encoded stability determinant par
Author(s) -
Weaver Keith E.,
Jensen Kristi D.,
Colwell Amy,
Sriram Saileela
Publication year - 1996
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.1996.tb02488.x
Subject(s) - biology , enterococcus faecalis , plasmid , microbiology and biotechnology , enterococcus , genetics , bacteria , staphylococcus aureus , gene , antibiotics
Summary The molecular organization and functional characteristics of the pAD1 replicon‐encoded par stability determinant were examined, par encodes two convergently transcribed RNAs of 210 and 65 nucleotides designated RNA I and RNA II, respectively. The sequence of RNA II is largely complementary to RNA I, suggesting that RNA II could regulate RNA I function as an anti‐sense RNA. Results of functional studies are consistent with a role for par as a post‐segregational killing system, the first to be identified in Gram‐positive bacteria, with RNA I encoding the toxin and RNA II the antidote. These results include: (i) destabilization of par ‐containing replicons in the presence of a second complete par or the RNA II coding sequence in the same cell; (ii) par ‐dependent stabilization of a highly unstable vector at the expense of host‐cell growth rate; and (iii) protection of cells from the toxic effects of overexpression of RNA I by RNA II supplied in trans .