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- Title
Tuning transcription of nutrient utilization genes to catabolic rate promotes growth in a gut bacterium.
- Authors
Raghavan, Varsha; Lowe, Elisabeth C.; Townsend, Guy E.; Bolam, David N.; Groisman, Eduardo A.
- Abstract
Cells respond to nutrient availability by expressing nutrient catabolic genes. We report that the regulator controlling utilization of chondroitin sulphate ( CS) in the mammalian gut symbiont B acteroides thetaiotaomicron is activated by an intermediate in CS breakdown rather than CS itself. We determine that the rate-determining enzyme in CS breakdown is responsible for degrading this intermediate and establish that the levels of the enzyme increase 100-fold, whereas those of the regulator remain constant upon exposure to CS. Because enzyme and regulator compete for the intermediate, B . thetaiotaomicron tunes transcription of CS utilization genes to CS catabolic rate. This tuning results in a transient increase in CS utilization transcripts upon exposure to excess CS. Constitutive expression of the rate-determining enzyme hindered activation of CS utilization genes and growth on CS. An analogous mechanism regulates heparin utilization genes, suggesting that the identified strategy aids B . thetaiotaomicron in the competitive gut environment.
- Subjects
BACTEROIDES thetaiotaomicron; GUT microbiome; GENETIC transcription; GENE expression; CHONDROITIN sulfates
- Publication
Molecular Microbiology, 2014, Vol 93, Issue 5, p1010
- ISSN
0950-382X
- Publication type
Article
- DOI
10.1111/mmi.12714