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Gurung, Jyoti
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Publications (5 of 5) Show all publications
Thanikkal, E. J., Kumar Gahlot, D., Liu, J., Fredriksson Sundbom, M., Gurung, J. M., Ruuth, K., . . . Francis, M. S. (2019). The Yersinia pseudotuberculosis Cpx envelope stress system contributes to transcriptional activation of rovM. Virulence, 10(1), 37-57
Open this publication in new window or tab >>The Yersinia pseudotuberculosis Cpx envelope stress system contributes to transcriptional activation of rovM
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2019 (English)In: Virulence, ISSN 2150-5594, E-ISSN 2150-5608, Vol. 10, no 1, p. 37-57Article in journal (Refereed) Published
Abstract [en]

The Gram-negative enteropathogen Yersinia pseudotuberculosis possesses a number of regulatory systems that detect cell envelope damage caused by noxious extracytoplasmic stresses. The CpxA sensor kinase and CpxR response regulator two-component regulatory system is one such pathway. Active Cpx signalling upregulates various factors designed to repair and restore cell envelope integrity. Concomitantly, this pathway also down-regulates key determinants of virulence. In Yersinia, cpxA deletion accumulates high levels of phosphorylated CpxR (CpxR~P). Accumulated CpxR~P directly repressed rovA expression and this limited expression of virulence-associated processes. A second transcriptional regulator, RovM, also negatively regulates rovA expression in response to nutrient stress. Hence, this study aimed to determine if CpxR~P can influence rovA expression through control of RovM levels. We determined that the active CpxR~P isoform bound to the promoter of rovM and directly induced its expression, which naturally associated with a concurrent reduction in rovA expression. Site-directed mutagenesis of the CpxR~P binding sequence in the rovM promoter region desensitised rovM expression to CpxR~P. These data suggest that accumulated CpxR~P inversely manipulates the levels of two global transcriptional regulators, RovA and RovM, and this would be expected to have considerable influence on Yersinia pathophysiology and metabolism.

Place, publisher, year, edition, pages
Taylor & Francis Group, 2019
Keywords
Environmental stress responsiveness, gene expression control, metabolic networks, microbial behaviour, growth and survival, fitness
National Category
Microbiology Microbiology in the medical area
Research subject
Microbiology; Molecular Biology; Infectious Diseases
Identifiers
urn:nbn:se:umu:diva-154425 (URN)10.1080/21505594.2018.1556151 (DOI)000453473300001 ()30518290 (PubMedID)
Funder
Swedish Research Council, 2009-3660Swedish Research Council, 2014-6652
Available from: 2018-12-17 Created: 2018-12-17 Last updated: 2019-03-05Bibliographically approved
Gurung, J. M., Amer, A., Francis, M., Costa, T., Chen, S., Zavialov, A. V. & Francis, M. S. (2018). Heterologous complementation studies with the YscX and YscY protein families reveals a specificity for Yersinia pseudotuberculosis type III secretion. Frontiers in Cellular and Infection Microbiology, 8, Article ID 80.
Open this publication in new window or tab >>Heterologous complementation studies with the YscX and YscY protein families reveals a specificity for Yersinia pseudotuberculosis type III secretion
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2018 (English)In: Frontiers in Cellular and Infection Microbiology, E-ISSN 2235-2988, Vol. 8, article id 80Article in journal (Refereed) Published
Abstract [en]

Type III secretion systems harbored by several Gram-negative bacteria are often used to deliver host-modulating effectors into infected eukaryotic cells. About 20 core proteins are needed for assembly of a secretion apparatus. Several of these proteins are genetically and functionally conserved in type III secretion systems of bacteria associated with invertebrate or vertebrate hosts. In the Ysc family of type III secretion systems are two poorly characterized protein families, the YscX family and the YscY family. In the plasmid-encoded Ysc-Yop type III secretion system of human pathogenic Yersinia species, YscX is a secreted substrate while YscY is its non-secreted cognate chaperone. Critically, neither an yscX nor yscY null mutant of Yersinia is capable of type III secretion. In this study, we show that the genetic equivalents of these proteins produced as components of other type III secretion systems of Pseudomonas aeruginosa (PscX and PscY), Aeromonas species (AscX and AscY), Vibrio species (VscX and VscY), and Photorhabdus luminescens (SctX and SctY) all possess an ability to interact with its native cognate partner and also establish cross-reciprocal binding to non-cognate partners as judged by a yeast two-hybrid assay. Moreover, a yeast three-hybrid assay also revealed that these heterodimeric complexes could maintain an interaction with YscV family members, a core membrane component of all type III secretion systems. Despite maintaining these molecular interactions, only expression of the native yscX in the near full-length yscX deletion and native yscY in the near full-length yscY deletion were able to complement for their general substrate secretion defects. Hence, YscX and YscY must have co-evolved to confer an important function specifically critical for Yersinia type III secretion.

Place, publisher, year, edition, pages
Frontiers Research Foundation, 2018
Keywords
T3S chaperone, secretion hierarchy, substrate sorting, LcrH/SycD, YscV, protein-protein interaction
National Category
Microbiology
Research subject
Microbiology; Molecular Biology; Infectious Diseases
Identifiers
urn:nbn:se:umu:diva-146348 (URN)10.3389/fcimb.2018.00080 (DOI)000427608900001 ()29616194 (PubMedID)
Funder
Swedish Research Council
Available from: 2018-04-05 Created: 2018-04-05 Last updated: 2018-06-09Bibliographically approved
Amer, A., Gurung, J., Costa, T., Ruuth, K., Zavialov, A., Forsberg, Å. & Francis, M. S. (2016). YopN and TyeA Hydrophobic Contacts Required for Regulating Ysc-Yop Type III Secretion Activity by Yersinia pseudotuberculosis. Frontiers in Cellular and Infection Microbiology, 6, Article ID 66.
Open this publication in new window or tab >>YopN and TyeA Hydrophobic Contacts Required for Regulating Ysc-Yop Type III Secretion Activity by Yersinia pseudotuberculosis
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2016 (English)In: Frontiers in Cellular and Infection Microbiology, E-ISSN 2235-2988, Vol. 6, article id 66Article in journal (Refereed) Published
Abstract [en]

Yersinia bacteria target Yop effector toxins to the interior of host immune cells by the Ysc-Yop type III secretion system. A YopN-TyeA heterodimer is central to controlling Ysc-Yop targeting activity. A + 1 frameshift event in the 3-prime end of yopN can also produce a singular secreted YopN-TyeA polypeptide that retains some regulatory function even though the C-terminal coding sequence of this YopN differs greatly from wild type. Thus, this YopN C-terminal segment was analyzed for its role in type III secretion control. Bacteria producing YopN truncated after residue 278, or with altered sequence between residues 279 and 287, had lost type III secretion control and function. In contrast, YopN variants with manipulated sequence beyond residue 287 maintained full control and function. Scrutiny of the YopN-TyeA complex structure revealed that residue W279 functioned as a likely hydrophobic contact site with TyeA. Indeed, a YopNW279G mutant lost all ability to bind TyeA. The TyeA residue F8 was also critical for reciprocal YopN binding. Thus, we conclude that specific hydrophobic contacts between opposing YopN and TyeA termini establishes a complex needed for regulating Ysc-Yop activity.

Keywords
protein-protein interaction, molecular modelling, protein secretion, mutagenesis, bacterial pathogenesis, regulation
National Category
Microbiology in the medical area Biochemistry and Molecular Biology
Research subject
Microbiology
Identifiers
urn:nbn:se:umu:diva-122904 (URN)10.3389/fcimb.2016.00066 (DOI)000378543500001 ()
Funder
Swedish Research Council
Available from: 2016-06-23 Created: 2016-06-23 Last updated: 2018-06-07Bibliographically approved
Song, T., Sabharwal, D., Gurung, J. M., Cheng, A. T., Sjöström, A. E., Yildiz, F. H., . . . Wai, S. N. (2014). Vibrio cholerae Utilizes Direct sRNA Regulation in Expression of a Biofilm Matrix Protein. PLoS ONE, 9(7), Article ID e101280.
Open this publication in new window or tab >>Vibrio cholerae Utilizes Direct sRNA Regulation in Expression of a Biofilm Matrix Protein
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2014 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, no 7, article id e101280Article in journal (Refereed) Published
Abstract [en]

Vibrio cholerae biofilms contain exopolysaccharide and three matrix proteins RbmA, RbmC and Bap1. While much is known about exopolysaccharide regulation, little is known about the mechanisms by which the matrix protein components of biofilms are regulated. VrrA is a conserved, 140-nt sRNA of V. cholerae, whose expression is controlled by sigma factor sigma(E). In this study, we demonstrate that VrrA negatively regulates rbmC translation by pairing to the 5' untranslated region of the rbmC transcript and that this regulation is not stringently dependent on the RNA chaperone protein Hfq. These results point to VrrA as a molecular link between the sigma(E)-regulon and biofilm formation in V. cholerae. In addition, VrrA represents the first example of direct regulation of sRNA on biofilm matrix component, by-passing global master regulators.

Place, publisher, year, edition, pages
PLOS, 2014
National Category
Cell and Molecular Biology Infectious Medicine Microbiology in the medical area
Identifiers
urn:nbn:se:umu:diva-92947 (URN)10.1371/journal.pone.0101280 (DOI)000339614100012 ()
Available from: 2014-09-15 Created: 2014-09-09 Last updated: 2018-06-07Bibliographically approved
Thanikkal, E., Obi, I., Liu, J., Gurung, J., Dersch, P. & Francis, M.The Yersinia pseudotuberculosis Cpx envelope stress system contributes to transcription activation of rovM.
Open this publication in new window or tab >>The Yersinia pseudotuberculosis Cpx envelope stress system contributes to transcription activation of rovM
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(English)Manuscript (preprint) (Other academic)
Keywords
extracytoplasmic stress, two-component signal transduction, gene regulation, virulence, nutrient availability
National Category
Microbiology
Research subject
Microbiology; Molecular Biology
Identifiers
urn:nbn:se:umu:diva-97337 (URN)
Available from: 2014-12-15 Created: 2014-12-15 Last updated: 2018-06-07Bibliographically approved
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