Translational regulation by an intramolecular stem-loop is required for intermolecular RNA regulation of the par addiction module.
The par stability determinant of Enterococcus faecalis plasmid pAD1 is the only antisense RNA-regulated addiction module identified to date in gram-positive bacteria. par encodes two small, convergently transcribed RNAs, designated RNA I and RNA II, that function as the toxin (Fst)-encoding and antitoxin components, respectively. Previous work showed that structures at the 5' end of RNA I are important in regulating its translation. The work presented here reveals that a stem-loop sequestering the Fst ribosome binding site is required for translational repression but a helix sequestering the 5' end of RNA I is not. Furthermore, disruption of the stem-loop prevented RNA II-mediated repression of Fst translation in vivo. Finally, although Fst-encoding wild-type RNA I is not toxic in Escherichia coli, mutations affecting stem-loop stability resulted in toxicity in this host, presumably due to increased translation.
Shokeen
Sonia
S
Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, SD 57069, USA.
Patel
Smita
S
Greenfield
Tony J
TJ
Brinkman
Cassandra
C
Weaver
Keith E
KE
D020121:5' Untranslated Regions / Q000737:chemistry / Q000235:genetics; D001427:Bacterial Toxins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D020029:Base Pairing; D015536:Down-Regulation; D013293:Enterococcus faecalis / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D014176:Protein Biosynthesis; D012329:RNA, Bacterial / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
D020121:5' Untranslated Regions; D001427:Bacterial Toxins; D012329:RNA, Bacterial; C473319:fst toxin, Enterococcus faecalis