Truncation of type IV pilin induces mucoidy in Pseudomonas aeruginosa strain PAO579

Pseudomonas aeruginosa is a Gram negative, opportunistic pathogen that uses the overproduction of alginate, a surface polysaccharide, to form biofilms in vivo. Overproduction of alginate, also known as mucoidy, affords the bacterium protection from the host's defenses and facilitates the establ...

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Main Authors:	Ryan Withers, T, Heath Damron, F, Yin, Yeshi, Yu, Hongwei D
Format:	Online
Language:	English
Published:	Blackwell Publishing Ltd 2013
Online Access:	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3684759/

id	pubmed-3684759
recordtype	oai_dc
spelling	pubmed-36847592013-06-20 Truncation of type IV pilin induces mucoidy in Pseudomonas aeruginosa strain PAO579 Ryan Withers, T Heath Damron, F Yin, Yeshi Yu, Hongwei D Original Research Pseudomonas aeruginosa is a Gram negative, opportunistic pathogen that uses the overproduction of alginate, a surface polysaccharide, to form biofilms in vivo. Overproduction of alginate, also known as mucoidy, affords the bacterium protection from the host's defenses and facilitates the establishment of chronic lung infections in individuals with cystic fibrosis. Expression of the alginate biosynthetic operon is primarily controlled by the alternative sigma factor AlgU (AlgT/σ22). In a nonmucoid strain, AlgU is sequestered by the transmembrane antisigma factor MucA to the cytoplasmic membrane. AlgU can be released from MucA via regulated intramembrane proteolysis by proteases AlgW and MucP causing the conversion to mucoidy. Pseudomonas aeruginosa strain PAO579, a derivative of the nonmucoid strain PAO1, is mucoid due to an unidentified mutation (muc-23). Using whole genome sequencing, we identified 16 nonsynonymous and 15 synonymous single nucleotide polymorphisms (SNP). We then identified three tandem single point mutations in the pilA gene (PA4525), as the cause of mucoidy in PAO579. These tandem mutations generate a premature stop codon resulting in a truncated version of PilA (PilA108), with a C-terminal motif of phenylalanine-threonine-phenylalanine (FTF). Inactivation of pilA108 confirmed it was required for mucoidy. Additionally, algW and algU were also required for mucoidy of PAO579. Western blot analysis indicated that MucA was less stable in PAO579 than nonmucoid PAO1 or PAO381. The mucoid phenotype and high PalgU and PalgD promoter activities of PAO579 require pilA108, algW, algU, and rpoN encoding the alternative sigma factor σ54. We also observed that RpoN regulates expression of algW and pilA in PAO579. Together, these results suggest that truncation in type IV pilin in P. aeruginosa strain PAO579 can induce mucoidy through an AlgW/AlgU-dependent pathway. Blackwell Publishing Ltd 2013-06 2013-03-27 /pmc/articles/PMC3684759/ /pubmed/23533140 http://dx.doi.org/10.1002/mbo3.86 Text en © 2013 Published by John Wiley & Sons Ltd. http://creativecommons.org/licenses/by/2.5/ Re-use of this article is permitted in accordance with the Creative Commons Deed, Attribution 2.5, which does not permit commercial exploitation.
repository_type	Open Access Journal
institution_category	Foreign Institution
institution	US National Center for Biotechnology Information
building	NCBI PubMed
collection	Online Access
language	English
format	Online
author	Ryan Withers, T Heath Damron, F Yin, Yeshi Yu, Hongwei D
spellingShingle	Ryan Withers, T Heath Damron, F Yin, Yeshi Yu, Hongwei D Truncation of type IV pilin induces mucoidy in Pseudomonas aeruginosa strain PAO579
author_facet	Ryan Withers, T Heath Damron, F Yin, Yeshi Yu, Hongwei D
author_sort	Ryan Withers, T
title	Truncation of type IV pilin induces mucoidy in Pseudomonas aeruginosa strain PAO579
title_short	Truncation of type IV pilin induces mucoidy in Pseudomonas aeruginosa strain PAO579
title_full	Truncation of type IV pilin induces mucoidy in Pseudomonas aeruginosa strain PAO579
title_fullStr	Truncation of type IV pilin induces mucoidy in Pseudomonas aeruginosa strain PAO579
title_full_unstemmed	Truncation of type IV pilin induces mucoidy in Pseudomonas aeruginosa strain PAO579
title_sort	truncation of type iv pilin induces mucoidy in pseudomonas aeruginosa strain pao579
description	Pseudomonas aeruginosa is a Gram negative, opportunistic pathogen that uses the overproduction of alginate, a surface polysaccharide, to form biofilms in vivo. Overproduction of alginate, also known as mucoidy, affords the bacterium protection from the host's defenses and facilitates the establishment of chronic lung infections in individuals with cystic fibrosis. Expression of the alginate biosynthetic operon is primarily controlled by the alternative sigma factor AlgU (AlgT/σ22). In a nonmucoid strain, AlgU is sequestered by the transmembrane antisigma factor MucA to the cytoplasmic membrane. AlgU can be released from MucA via regulated intramembrane proteolysis by proteases AlgW and MucP causing the conversion to mucoidy. Pseudomonas aeruginosa strain PAO579, a derivative of the nonmucoid strain PAO1, is mucoid due to an unidentified mutation (muc-23). Using whole genome sequencing, we identified 16 nonsynonymous and 15 synonymous single nucleotide polymorphisms (SNP). We then identified three tandem single point mutations in the pilA gene (PA4525), as the cause of mucoidy in PAO579. These tandem mutations generate a premature stop codon resulting in a truncated version of PilA (PilA108), with a C-terminal motif of phenylalanine-threonine-phenylalanine (FTF). Inactivation of pilA108 confirmed it was required for mucoidy. Additionally, algW and algU were also required for mucoidy of PAO579. Western blot analysis indicated that MucA was less stable in PAO579 than nonmucoid PAO1 or PAO381. The mucoid phenotype and high PalgU and PalgD promoter activities of PAO579 require pilA108, algW, algU, and rpoN encoding the alternative sigma factor σ54. We also observed that RpoN regulates expression of algW and pilA in PAO579. Together, these results suggest that truncation in type IV pilin in P. aeruginosa strain PAO579 can induce mucoidy through an AlgW/AlgU-dependent pathway.
publisher	Blackwell Publishing Ltd
publishDate	2013
url	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3684759/
_version_	1611987025998643200

Truncation of type IV pilin induces mucoidy in Pseudomonas aeruginosa strain PAO579

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