In:
Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 110, No. 32 ( 2013-08-06), p. 13132-13137
Kurzfassung:
Riboswitches are ligand-binding elements located in 5′ untranslated regions of messenger RNAs, which regulate expression of downstream genes. In Listeria monocytogenes , a vitamin B 12 -binding (B 12 ) riboswitch was identified, not upstream of a gene but downstream, and antisense to the adjacent gene, pocR, suggesting it might regulate pocR in a nonclassical manner. In Salmonella enterica, PocR is a transcription factor that is activated by 1,2-propanediol, and subsequently activates expression of the pdu genes. The pdu genes mediate propanediol catabolism and are implicated in pathogenesis. As enzymes involved in propanediol catabolism require B 12 as a cofactor, we hypothesized that the Listeria B 12 riboswitch might be involved in pocR regulation. Here we demonstrate that the B 12 riboswitch is transcribed as part of a noncoding antisense RNA, herein named AspocR. In the presence of B 12 , the riboswitch induces transcriptional termination, causing aspocR to be transcribed as a short transcript. In contrast, in the absence of B 12 , aspocR is transcribed as a long antisense RNA, which inhibits pocR expression. Regulation by AspocR ensures that pocR , and consequently the pdu genes, are maximally expressed only when both propanediol and B 12 are present. Strikingly, AspocR can inhibit pocR expression in trans , suggesting it acts through a direct interaction with pocR mRNA. Together, this study demonstrates how pocR and the pdu genes can be regulated by B 12 in bacteria and extends the classical definition of riboswitches from elements governing solely the expression of mRNAs to a wider role in controlling transcription of noncoding RNAs.
Materialart:
Online-Ressource
ISSN:
0027-8424
,
1091-6490
DOI:
10.1073/pnas.1304795110
Sprache:
Englisch
Verlag:
Proceedings of the National Academy of Sciences
Publikationsdatum:
2013
ZDB Id:
209104-5
ZDB Id:
1461794-8
SSG:
11
SSG:
12
Bookmarklink
