A bipartite iron-dependent transcriptional regulation of the tryptophan salvage pathway in Chlamydia trachomatis

• Published in: eLife Vol. 8
• Main Authors: Pokorzynski, Nick D, Brinkworth, Amanda J, Carabeo, Rey
• Format: Journal Article
• Language: English
• Published: England eLife Science Publications, Ltd 02-04-2019; eLife Sciences Publications Ltd; eLife Sciences Publications, Ltd
• Subjects: Amino acids; Bacteria; Bacterial genetics; Bacterial Proteins - metabolism; Blindness; Cells (Biology); Cellular stress response; Childrens health; Chlamydia; Chlamydia infections; Chlamydia trachomatis; Chlamydia trachomatis - genetics; Chlamydia trachomatis - metabolism; Chromosomes and Gene Expression; Disease transmission; DNA; Future predictions; Gene expression; Gene Expression Regulation, Bacterial; Gene regulation; Genes; Genetic aspects; Genetic regulation; Genomes; Genomics; Immune system; Infection; Infertility; Iron; Iron - metabolism; iron-dependent regulation; Metabolic Networks and Pathways - genetics; Microbiology and Infectious Disease; Microorganisms; Nutrients; Observations; Operon; Pathogenic microorganisms; Pathogens; Physiological aspects; Promoter Regions, Genetic; Proteins; repression; Repressor Proteins - metabolism; Sexually transmitted diseases; Shortages; Stress response; Transcription; Transcription (Genetics); Transcription, Genetic; Tryptophan; Tryptophan - metabolism; tryptophan biosynthesis; Variance analysis; United States; United States > US; tryptophan biosynthesis; stress response; transcription; infectious disease; chromosomes; iron-dependent regulation; microbiology; Chlamydia trachomatis; repression; gene expression
• ISSN: 2050-084X; 2050-084X
• DOI: 10.7554/eLife.42295

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
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
tryptophan salvage pathway in
Iron starvation specifically induces
expression from a novel promoter element within an intergenic region flanked by
and
. YtgR, the only known iron-dependent regulator in
, can bind to the
intergenic region upstream of the alternative
promoter to repress transcription. Simultaneously, YtgR binding promotes the termination of transcripts from the primary promoter upstream of
. 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