The transcriptional regulator LysG (Rv1985c) of Mycobacterium tuberculosis activates lysE (Rv1986) in a lysine-dependent manner

PLoS One. 2017 Oct 19;12(10):e0186505. doi: 10.1371/journal.pone.0186505. eCollection 2017.

Abstract

The Mycobacterium tuberculosis protein encoded by the Rv1986 gene is a target for memory T cells in patients with tuberculosis, and shows strong similarities to a lysine exporter LysE of Corynebacterium glutamicum. During infection, the pathogen Mycobacterium tuberculosis adapts its metabolism to environmental changes. In this study, we found that the expression of Rv1986 is controlled by Rv1985c. Rv1985c is located directly upstream of Rv1986 with an overlapping promoter region between both genes. Semiquantitative reverse transcription PCR using an isogenic mutant of Mycobacterium tuberculosis lacking Rv1985c showed that in the presence of lysine, Rv1985c protein positively upregulated the expression of Rv1986. RNA sequencing revealed the transcription start points for both transcripts and overlapping promoters. An inverted repeat in the center of the intergenic region was identified, and binding of Rv1985c protein to the intergenic region was confirmed by electrophoretic mobility shift assays. Whole transcriptome expression analysis and RNAsequencing showed downregulated transcription of ppsBCD in the Rv1985c-mutant compared to the wild type strain. Taken together, our findings characterize the regulatory network of Rv1985c in Mycobacterium tuberculosis. Due to their similarity of an orthologous gene pair in Corynebacterium glutamicum, we suggest to rename Rv1985c to lysG(Mt), and Rv1986 to lysE(Mt).

MeSH terms

  • Amino Acid Sequence
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Electrophoretic Mobility Shift Assay
  • Gene Expression Regulation, Bacterial
  • Genes, Bacterial
  • Lysine / metabolism*
  • Mycobacterium tuberculosis / genetics
  • Mycobacterium tuberculosis / metabolism*
  • Promoter Regions, Genetic
  • Reverse Transcriptase Polymerase Chain Reaction
  • Sequence Homology, Amino Acid
  • Trans-Activators / chemistry
  • Trans-Activators / genetics
  • Trans-Activators / metabolism*
  • Transcriptome

Substances

  • Bacterial Proteins
  • Trans-Activators
  • Lysine

Grants and funding

This work was supported by Niedersächsischer Verein zur Bekämpfung der Tuberkulose, Lungen- und Bronchialerkrankungen; FCB. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.