A bipartite iron-dependent transcriptional regulation of the tryptophan salvage pathway in Chlamydia trachomatis
Abstract
During infection, pathogens are starved of essential nutrients such as iron and tryptophan by host immune effectors. Without conserved global stress response regulators, how the obligate intracellular bacterium Chlamydia trachomatis arrives at a physiologically similar 'persistent' state in response to starvation of either nutrient remains unclear. Here, we report on the iron-dependent regulation of the trpRBA tryptophan salvage pathway in C. trachomatis. Iron starvation specifically induces trpBA expression from a novel promoter element within an intergenic region flanked by trpR and trpB. YtgR, the only known iron-dependent regulator in Chlamydia, can bind to the trpRBA intergenic region upstream of the alternative trpBA promoter to repress transcription. Simultaneously, YtgR binding promotes the termination of transcripts from the primary promoter upstream of trpR. This is the first description of an iron-dependent mechanism regulating prokaryotic tryptophan biosynthesis that may indicate the existence of novel approaches to gene regulation and stress response in Chlamydia.
Data availability
Raw and processed sequencing data have been deposited in the Gene Expression Omnibus (Accesssion number GSE106763).
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Transcriptional response of C.trachomatis to early-cycle and mid-cycle iron-starvationGene Expression Omnibus, GSE106763.
Article and author information
Author details
Funding
National Institutes of Health (AI065545)
- Rey Carabeo
Achievement Rewards for College Scientists Foundation
- Nick D Pokorzynski
National Institutes of Health (F31AI136295)
- Nick D Pokorzynski
National Institutes of Health (T32GM008336)
- Nick D Pokorzynski
National Institutes of Health (T32AI007025)
- Amanda J Brinkworth
National Institutes of Health (AI132406)
- Rey Carabeo
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2019, Pokorzynski et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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