Journal
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
Volume 101, Issue 26, Pages 9792-9797Publisher
NATL ACAD SCIENCES
DOI: 10.1073/pnas.0403423101
Keywords
-
Categories
Funding
- NIAID NIH HHS [AI15940, R37 AI015940, R01 AI015940] Funding Source: Medline
Ask authors/readers for more resources
In many bacteria, iron homeostasis is controlled primarily by the ferric uptake regulator (Fur), a transcriptional repressor. However, some genes, including those involved in iron storage, are positively regulated by Fur. A Fur-repressed regulatory small RNA (sRNA), RyhB, has been identified in Escherichia coli, and it has been demonstrated that negative regulation of genes by this sRNA is responsible for the positive regulation of some genes by Fur. No RyhB sequence homologs were found in Pseudomonas aeruginosa, despite the identification of genes positively regulated by its Fur homolog. A bioinformatics approach identified two tandem sRNAs in P. aeruginosa that were candidates for functional homologs of RyhB. These sRNAs (PrrF1 and PrrF2) are >95% identical to each other, and a functional Fur box precedes each. Their expression is induced under iron limitation. Deletion of both sRNAs is required to affect the iron-dependent regulation of an array of genes, including those involved in resistance to oxidative stress, iron storage, and intermediary metabolism. As in E. coli, induction of the PrrF sRNAs leads to the rapid loss of mRNAs for sodB (superoxide dismutase), sdh (succinate dehydrogenase), and a gene encoding a bacterioferritin. Thus, the PrrF sRNAs are the functional homologs of RyhB sRNA. At least one gene, bfrB, is positively regulated by Fur and Fe2+, even in the absence of the PrrF sRNAs. This work suggests that the role of sRNAs in bacterial iron homeostasis may be broad, and approaches similar to those described here may identify these sRNAs in other organisms.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available