Functional analysis of the Enterococcus faecalis plasmid pAD1-encoded stability determinant par.
The molecular organization and functional characteristics of the PAD1 replicon-encoded par stability determinant were examined. par encodes two convergently transcribed RNAS of approximately 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.
Weaver
K E
KE
Department of Microbiology, School of Medicine, University of South Dakota, Vermillion 57069, USA.
Jensen
K D
KD
Colwell
A
A
Sriram
S I
SI
D001483:Base Sequence; D013293:Enterococcus faecalis / Q000235:genetics* / Q000254:growth & development; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D010957:Plasmids; D011401:Promoter Regions, Genetic; D012329:RNA, Bacterial / Q000096:biosynthesis / Q000235:genetics*; D012093:Replicon
D012329:RNA, Bacterial