Phenotypic Profiling of Mycobacterium tuberculosis EspA Point Mutants Reveals that Blockage of ESAT-6 and CFP-10 Secretion In Vitro Does Not Always Correlate with Attenuation of Virulence | Zendy

Jeffrey M. Chen | Zendy; Ming Zhang | Zendy; Jan Rybniker | Zendy; Laetitia Basterra | Zendy; Neeraj Dhar | Zendy; Anna D. Tischler | Zendy; Florence Pojer | Zendy; Stewart T. Cole | Zendy

Open Access

Phenotypic Profiling of Mycobacterium tuberculosis EspA Point Mutants Reveals that Blockage of ESAT-6 and CFP-10 Secretion In Vitro Does Not Always Correlate with Attenuation of Virulence

Author(s) -

Jeffrey M. Chen,

Ming Zhang,

Jan Rybniker,

Laetitia Basterra,

Neeraj Dhar,

Anna D. Tischler,

Florence Pojer,

Stewart T. Cole

Publication year - 2013

Publication title -

journal of bacteriology

Language(s) - English

Resource type - Journals

SCImago Journal Rank - 1.652

H-Index - 246

eISSN - 1067-8832

pISSN - 0021-9193

DOI - 10.1128/jb.00967-13

Subject(s) - biology , esat 6 , virulence , phenotype , mycobacterium tuberculosis , microbiology and biotechnology , secretion , mycobacterium , tuberculosis , mutant , in vitro , genetics , bacterial protein , bacteria , gene , pathology , medicine , biochemistry

The EspA protein ofMycobacterium tuberculosis is essential for the type VII ESX-1 protein secretion apparatus, which delivers the principal virulence factors ESAT-6 and CFP-10. In this study, site-directed mutagenesis of EspA was performed to elucidate its influence on the ESX-1 system. Replacing Trp55 (W55) or Gly57 (G57) residues in the putative W-X-G motif of EspA with arginines impaired ESAT-6 and CFP-10 secretionin vitro and attenuatedM. tuberculosis . Replacing the Phe50 (F50) and Lys62 (K62) residues, which flank the W-X-G motif, with arginine and alanine, respectively, destabilized EspA, abolished ESAT-6 and CFP-10 secretionin vitro , and attenuatedM. tuberculosis . Likewise, replacing the Phe5 (F5) and Lys41 (K41) residues with arginine and alanine, respectively, also destabilized EspA and blocked ESAT-6 and CFP-10 secretionin vitro . However, these two particular mutations did not attenuateM. tuberculosis in cellular models of infection or during acute infection in mice. We have thus identified amino acid residues in EspA that are important for facilitating ESAT-6 and CFP-10 secretion and virulence. However, our data also indicate for the first time that blockage ofM. tuberculosis ESAT-6 and CFP-10 secretionin vitro and attenuation are mutually exclusive.

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