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BosR Functions as a Repressor of the ospAB Operon in Borrelia burgdorferi

The Lyme disease spirochete, Borrelia burgdorferi, must abundantly produce outer surface lipoprotein A (OspA) in the tick vector but downregulate OspA in mammals in order to evade the immune system and maintain its natural enzootic cycle. Here, we show that BosR binds two regulatory elements of the...

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Autores principales: Shi, Yanlin, Dadhwal, Poonam, Li, Xin, Liang, Fang Ting
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2014
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4182837/
https://www.ncbi.nlm.nih.gov/pubmed/25271631
http://dx.doi.org/10.1371/journal.pone.0109307
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author Shi, Yanlin
Dadhwal, Poonam
Li, Xin
Liang, Fang Ting
author_facet Shi, Yanlin
Dadhwal, Poonam
Li, Xin
Liang, Fang Ting
author_sort Shi, Yanlin
collection PubMed
description The Lyme disease spirochete, Borrelia burgdorferi, must abundantly produce outer surface lipoprotein A (OspA) in the tick vector but downregulate OspA in mammals in order to evade the immune system and maintain its natural enzootic cycle. Here, we show that BosR binds two regulatory elements of the ospAB operon and that increasing BosR expression leads to downregulation of OspA. Both regulatory sequences, cisI and cisII, showed strong BosR-binding and cisII bound much tighter than cisI. A promoterless bosR gene fused with an inducible promoter was introduced into an rpoS mutant and a wild-type strain to assess RpoS-independent and -dependent downregulation of OspA by BosR. With the induction of BosR expression, OspA expression was reduced more significantly in the RpoS-deficient than wild-type background, but not completely repressed. In the presence of constitutive expression of OspC, DbpA and DbpB, increasing BosR production resulted in complete repression of OspA in the RpoS mutant. Taken together, the study clearly demonstrated BosR serves as a repressor that binds both regulatory elements of the ospAB operon and shuts off expression.
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spelling pubmed-41828372014-10-07 BosR Functions as a Repressor of the ospAB Operon in Borrelia burgdorferi Shi, Yanlin Dadhwal, Poonam Li, Xin Liang, Fang Ting PLoS One Research Article The Lyme disease spirochete, Borrelia burgdorferi, must abundantly produce outer surface lipoprotein A (OspA) in the tick vector but downregulate OspA in mammals in order to evade the immune system and maintain its natural enzootic cycle. Here, we show that BosR binds two regulatory elements of the ospAB operon and that increasing BosR expression leads to downregulation of OspA. Both regulatory sequences, cisI and cisII, showed strong BosR-binding and cisII bound much tighter than cisI. A promoterless bosR gene fused with an inducible promoter was introduced into an rpoS mutant and a wild-type strain to assess RpoS-independent and -dependent downregulation of OspA by BosR. With the induction of BosR expression, OspA expression was reduced more significantly in the RpoS-deficient than wild-type background, but not completely repressed. In the presence of constitutive expression of OspC, DbpA and DbpB, increasing BosR production resulted in complete repression of OspA in the RpoS mutant. Taken together, the study clearly demonstrated BosR serves as a repressor that binds both regulatory elements of the ospAB operon and shuts off expression. Public Library of Science 2014-10-01 /pmc/articles/PMC4182837/ /pubmed/25271631 http://dx.doi.org/10.1371/journal.pone.0109307 Text en © 2014 Shi et al http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
spellingShingle Research Article
Shi, Yanlin
Dadhwal, Poonam
Li, Xin
Liang, Fang Ting
BosR Functions as a Repressor of the ospAB Operon in Borrelia burgdorferi
title BosR Functions as a Repressor of the ospAB Operon in Borrelia burgdorferi
title_full BosR Functions as a Repressor of the ospAB Operon in Borrelia burgdorferi
title_fullStr BosR Functions as a Repressor of the ospAB Operon in Borrelia burgdorferi
title_full_unstemmed BosR Functions as a Repressor of the ospAB Operon in Borrelia burgdorferi
title_short BosR Functions as a Repressor of the ospAB Operon in Borrelia burgdorferi
title_sort bosr functions as a repressor of the ospab operon in borrelia burgdorferi
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4182837/
https://www.ncbi.nlm.nih.gov/pubmed/25271631
http://dx.doi.org/10.1371/journal.pone.0109307
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