title: Novel iron-regulated and Fur-regulated small regulatory RNAs in Aggregatibacter actinomycetemcomitans.
abstract: Iron can regulate biofilm formation via non-coding small RNA (sRNA). To determine if iron-regulated sRNAs are involved in biofilm formation by the periodontopathogen Aggregatibacter actinomycetemcomitans, total RNA was isolated from bacteria cultured with iron supplementation or chelation. Transcriptional analysis demonstrated that the expression of four sRNA molecules (JA01-JA04) identified by bioinformatics was significantly upregulated in iron-limited medium compared with iron-rich medium. A DNA fragment encoding each sRNA promoter was able to titrate Escherichia coli ferric uptake regulator (Fur) from a Fur-repressible reporter fusion in an iron uptake regulator titration assay. Cell lysates containing recombinant AaFur shifted the mobility of sRNA-specific DNAs in a gel shift assay. Potential targets of these sRNAs, determined in silico, included genes involved in biofilm formation. The A. actinomycetemcomitans overexpressing JA03 sRNA maintained a rough phenotype on agar, but no longer adhered to uncoated polystyrene or glass, although biofilm determinant gene expression was only modestly decreased. In summary, these sRNAs have the ability to modulate biofilm formation, but their functional target genes remain to be confirmed.
authors.affiliation: Department of Oral Biology, School of Dental Medicine, University at Buffalo, State University of New York, Buffalo, NY 14214, USA.
authors.forename: J J
authors.initials: JJ
authors.lastname: Amarasinghe
authors.forename: T D
authors.initials: TD
authors.lastname: Connell
authors.forename: F A
authors.initials: FA
authors.lastname: Scannapieco
authors.forename: E M
authors.initials: EM
authors.lastname: Haase
mesh_terms: D016976:Aggregatibacter actinomycetemcomitans / Q000235:genetics*; D001422:Bacterial Adhesion / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D018441:Biofilms / Q000254:growth & development; D016384:Consensus Sequence / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics; D017930:Genes, Reporter / Q000235:genetics; D006801:Humans; D007501:Iron / Q000378:metabolism*; D008667:Metalloproteins / Q000378:metabolism*; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D010957:Plasmids / Q000235:genetics; D012329:RNA, Bacterial / Q000235:genetics*; D058727:RNA, Small Untranslated / Q000235:genetics*; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D015534:Trans-Activators / Q000378:metabolism*; D014158:Transcription, Genetic / Q000235:genetics; D015854:Up-Regulation
chemical_list: D001426:Bacterial Proteins; D008667:Metalloproteins; D012329:RNA, Bacterial; D058727:RNA, Small Untranslated; D012097:Repressor Proteins; D015534:Trans-Activators; C068477:ferric uptake regulating proteins, bacterial; D007501:Iron