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Environ Microbiol. 2010 Jul;12(7):2034-47. doi: 10.1111/j.1462-2920.2010.02219.x. Epub 2010 Apr 19.

Polyamines are required for the expression of key Hms proteins important for Yersinia pestis biofilm formation.

Author information

1
Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY 40536, USA.

Abstract

We previously showed that mutations in the genes encoding the two main biosynthetic enzymes responsible for polyamine production, arginine decarboxylase (SpeA) and ornithine decarboxylase (SpeC) cause a loss of biofilm formation in Yersinia pestis. In Y. pestis the development of a biofilm is dependent on 6 Hms (hemin storage) proteins (HmsH, F, R, S, T and P) grouped into 3 operons; hmsHFRS, hmsT and hmsP. In this article we show that polyamines are necessary to maintain the levels of key Hms proteins. In the absence of polyamines there is an approximately 93%, approximately 43% and approximately 90% reduction in protein levels of HmsR, HmsS and HmsT respectively. Overexpression of hmsR and hmsT from plasmids alone can restore biofilm formation to a SpeA(-)SpeC(-) mutant. Addition of exogenous putrescine also restores normal levels of HmsR, HmsS, HmsT and biofilm production. Analyses using transcriptional reporters and quantitative RT-PCR indicate that the initiation of transcription and mRNA stability are not reduced by polyamine deficiency. Instead, translational reporters indicate that polyamines function at least in part by modulating the translation of HmsR and HmsT. Although construction of a consensus Shine-Dalgarno sequence upstream of hmsT modestly reduced the stimulation of translation by putrescine, additional mechanisms likely contribute to the polyamine-dependent expression of HmsT. Finally, we have shown that polyamines play a role in bubonic plague.

PMID:
20406298
PMCID:
PMC3039482
DOI:
10.1111/j.1462-2920.2010.02219.x
[Indexed for MEDLINE]
Free PMC Article

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