Abstract
Bacterial growth and division require regulated synthesis of the macromolecules used to expand and replicate components of the cell. Transcription of housekeeping genes required for metabolic homeostasis and cell proliferation is guided by the sigma factor σ70. The conserved CarD-like transcriptional regulator, CdnL, associates with promoter regions where σ70 localizes and stabilizes the open promoter complex. However, the contributions of CdnL to metabolic homeostasis and bacterial physiology are not well understood. Here, we show that Caulobacter crescentus cells lacking CdnL have severe morphological and growth defects. Specifically, ΔcdnL cells grow slowly in both rich and defined media, and are wider, more curved, and have shorter stalks than WT cells. These defects arise from transcriptional downregulation of most major classes of biosynthetic genes, leading to significant decreases in the levels of critical metabolites, including pyruvate, α-ketoglutarate, ATP, NAD+, UDP-N-acetyl-glucosamine, lipid II, and purine and pyrimidine precursors. Notably, we find that ΔcdnL cells are glutamate auxotrophs, and ΔcdnL is synthetic lethal with other genetic perturbations that limit glutamate synthesis and lipid II production. Our findings implicate CdnL as a direct and indirect regulator of genes required for metabolic homeostasis that impacts morphogenesis through availability of lipid II and other metabolites.
Highlights
In order to replicate, bacterial cells must synthesize enough macromolecules to double in size using nutrients available in their environment
CdnL regulates metabolism and morphogenesis in Caulobacter ncbi.nlm.nih.gov/geo/query/acc.cgi?acc= GSE139873), and ChIP-seq data are publicly available in NCBI
We observed occasional cell filamentation for ΔcdnL cells grown in peptone yeast extract medium (PYE), but this was not the predominant shape defect
Summary
Bacterial cells must synthesize enough macromolecules to double in size using nutrients available in their environment. CdnL is broadly conserved in bacteria and is best-characterized in Myxococcus xanthus and in Mycobacteria [2,3,4,5,6] It localizes to promoter regions where the housekeeping sigma factor resides, directly binds to the RNAP β subunit, stabilizes the open promoter complex, and is required for transcription from rRNA promoters [2,3,5]. The Borrelia burgdorferi CdnL homolog LtpA is important for infection and is upregulated during cold shock [9,10] These observations suggest that CdnL plays a role in stress response in diverse bacteria in addition to its role in mediating transcription of housekeeping genes
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
