Identification of the <it>Streptococcus mutans</it> LytST two-component regulon reveals its contribution to oxidative stress tolerance
<p>Abstract</p> <p>Background</p> <p>The <it>S. mutans</it> LrgA/B holin-like proteins have been shown to affect biofilm formation and oxidative stress tolerance, and are regulated by oxygenation, glucose levels, and by the LytST two-component system. In thi...
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| Format: | Article |
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BMC
2012-09-01
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| Series: | BMC Microbiology |
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| Online Access: | http://www.biomedcentral.com/1471-2180/12/187 |
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| author | Ahn Sang-Joon Qu Ming-Da Roberts Elisha Burne Robert A Rice Kelly C |
| author_facet | Ahn Sang-Joon Qu Ming-Da Roberts Elisha Burne Robert A Rice Kelly C |
| author_sort | Ahn Sang-Joon |
| collection | DOAJ |
| description | <p>Abstract</p> <p>Background</p> <p>The <it>S. mutans</it> LrgA/B holin-like proteins have been shown to affect biofilm formation and oxidative stress tolerance, and are regulated by oxygenation, glucose levels, and by the LytST two-component system. In this study, we sought to determine if LytST was involved in regulating <it>lrgAB</it> expression in response to glucose and oxygenation in <it>S. mutans</it>.</p> <p>Results</p> <p>Real-time PCR revealed that growth phase-dependent regulation of <it>lrgAB</it> expression in response to glucose metabolism is mediated by LytST under low-oxygen conditions. However, the effect of LytST on <it>lrgAB</it> expression was less pronounced when cells were grown with aeration. RNA expression profiles in the wild-type and <it>lytS</it> mutant strains were compared using microarrays in early exponential and late exponential phase cells. The expression of 40 and 136 genes in early-exponential and late exponential phase, respectively, was altered in the <it>lytS</it> mutant. Although expression of <it>comYB</it>, encoding a DNA binding-uptake protein, was substantially increased in the <it>lytS</it> mutant, this did not translate to an effect on competence. However, a <it>lrgA</it> mutant displayed a substantial decrease in transformation efficiency, suggestive of a previously-unknown link between LrgA and <it>S. mutans</it> competence development. Finally, increased expression of genes encoding antioxidant and DNA recombination/repair enzymes was observed in the <it>lytS</it> mutant, suggesting that the mutant may be subjected to increased oxidative stress during normal growth. Although the intracellular levels of reaction oxygen species (ROS) appeared similar between wild-type and <it>lytS</it> mutant strains after overnight growth, challenge of these strains with hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) resulted in increased intracellular ROS in the <it>lytS</it> mutant.</p> <p>Conclusions</p> <p>Overall, these results: (1) Reinforce the importance of LytST in governing <it>lrgAB</it> expression in response to glucose and oxygen, (2) Define a new role for LytST in global gene regulation and resistance to H<sub>2</sub>O<sub>2</sub>, and (3) Uncover a potential link between LrgAB and competence development in <it>S. mutans</it>.</p> |
| first_indexed | 2024-12-14T01:23:30Z |
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| spelling | doaj.art-a6c9ca71d9a34810b99d8024dc3052122022-12-21T23:22:17ZengBMCBMC Microbiology1471-21802012-09-0112118710.1186/1471-2180-12-187Identification of the <it>Streptococcus mutans</it> LytST two-component regulon reveals its contribution to oxidative stress toleranceAhn Sang-JoonQu Ming-DaRoberts ElishaBurne Robert ARice Kelly C<p>Abstract</p> <p>Background</p> <p>The <it>S. mutans</it> LrgA/B holin-like proteins have been shown to affect biofilm formation and oxidative stress tolerance, and are regulated by oxygenation, glucose levels, and by the LytST two-component system. In this study, we sought to determine if LytST was involved in regulating <it>lrgAB</it> expression in response to glucose and oxygenation in <it>S. mutans</it>.</p> <p>Results</p> <p>Real-time PCR revealed that growth phase-dependent regulation of <it>lrgAB</it> expression in response to glucose metabolism is mediated by LytST under low-oxygen conditions. However, the effect of LytST on <it>lrgAB</it> expression was less pronounced when cells were grown with aeration. RNA expression profiles in the wild-type and <it>lytS</it> mutant strains were compared using microarrays in early exponential and late exponential phase cells. The expression of 40 and 136 genes in early-exponential and late exponential phase, respectively, was altered in the <it>lytS</it> mutant. Although expression of <it>comYB</it>, encoding a DNA binding-uptake protein, was substantially increased in the <it>lytS</it> mutant, this did not translate to an effect on competence. However, a <it>lrgA</it> mutant displayed a substantial decrease in transformation efficiency, suggestive of a previously-unknown link between LrgA and <it>S. mutans</it> competence development. Finally, increased expression of genes encoding antioxidant and DNA recombination/repair enzymes was observed in the <it>lytS</it> mutant, suggesting that the mutant may be subjected to increased oxidative stress during normal growth. Although the intracellular levels of reaction oxygen species (ROS) appeared similar between wild-type and <it>lytS</it> mutant strains after overnight growth, challenge of these strains with hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) resulted in increased intracellular ROS in the <it>lytS</it> mutant.</p> <p>Conclusions</p> <p>Overall, these results: (1) Reinforce the importance of LytST in governing <it>lrgAB</it> expression in response to glucose and oxygen, (2) Define a new role for LytST in global gene regulation and resistance to H<sub>2</sub>O<sub>2</sub>, and (3) Uncover a potential link between LrgAB and competence development in <it>S. mutans</it>.</p>http://www.biomedcentral.com/1471-2180/12/187StressOxygenCompetenceCid/Lrg system<it>Streptococcus mutans</it> |
| spellingShingle | Ahn Sang-Joon Qu Ming-Da Roberts Elisha Burne Robert A Rice Kelly C Identification of the <it>Streptococcus mutans</it> LytST two-component regulon reveals its contribution to oxidative stress tolerance BMC Microbiology Stress Oxygen Competence Cid/Lrg system <it>Streptococcus mutans</it> |
| title | Identification of the <it>Streptococcus mutans</it> LytST two-component regulon reveals its contribution to oxidative stress tolerance |
| title_full | Identification of the <it>Streptococcus mutans</it> LytST two-component regulon reveals its contribution to oxidative stress tolerance |
| title_fullStr | Identification of the <it>Streptococcus mutans</it> LytST two-component regulon reveals its contribution to oxidative stress tolerance |
| title_full_unstemmed | Identification of the <it>Streptococcus mutans</it> LytST two-component regulon reveals its contribution to oxidative stress tolerance |
| title_short | Identification of the <it>Streptococcus mutans</it> LytST two-component regulon reveals its contribution to oxidative stress tolerance |
| title_sort | identification of the it streptococcus mutans it lytst two component regulon reveals its contribution to oxidative stress tolerance |
| topic | Stress Oxygen Competence Cid/Lrg system <it>Streptococcus mutans</it> |
| url | http://www.biomedcentral.com/1471-2180/12/187 |
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