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Mycobacterium leprae hsp18 promoter-EGFP transcriptional fusion construct: Environmental stress and strain-specific

Elenjikal A Rehna1, Hussain Munavar2, Kuppamuthu Dharmalingam3

  • 1Department of Genetic Engineering, School of Biotechnology, Madurai Kamaraj University, Madurai 625021, India; Department of Molecular Microbiology, School of Biotechnology, Madurai 625021, India.

Gene
|November 12, 2022
PubMed

Insights

This study characterizes the Mycobacterium leprae hsp18 promoter, revealing its transcriptional regulation is influenced by host, stress, and temperature. This finding is crucial for understanding leprosy pathogenesis and developing new diagnostics.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Genetics

Background:

  • Hsp18 is a key T-cell antigen in Mycobacterium leprae, crucial for bacterial survival.
  • Its post-translational regulation suggests significant importance, yet its promoter and genetic regulation remain uncharacterized.

Purpose of the Study:

  • To characterize the hsp18 promoter of Mycobacterium leprae.
  • To investigate the genetic regulation of hsp18 expression under various environmental conditions.

Main Methods:

  • Constructed an hsp18-EGFP transcriptional fusion using an E. coli-Mycobacterium shuttle vector.
  • Cloned a 168-bp hsp18 promoter sequence upstream of EGFP and transformed into M. smegmatis and E. coli.
  • Analyzed EGFP expression under different environmental stresses and temperatures.

Main Results:

  • The 168-bp sequence functions as a promoter, with expression dependent on host, stress, and temperature.
  • EGFP expression was higher in M. smegmatis under stress; E. coli showed expression only under stress.
  • Identified a putative sigma factor C (SigC)-binding site in the hsp18 promoter sequence.

Conclusions:

  • Hsp18 expression is transcriptionally regulated by environmental stress, potentially via SigC in Mycobacterium.
  • The developed shuttle vector facilitates functional gene characterization in heterologous systems.
  • Findings offer insights into M. leprae survival mechanisms and potential therapeutic targets.
Keywords:
Mycobacterium lepraeSmall heat-shock proteinT-cell antigen

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