MAG2, a toxoplasma gondii bradyzoite stage-specific cyst matrix protein

Vincent Tu, Joshua Mayoral, Rama R. Yakubu, Tadakimi Tomita, Tatsuki Sugi, Bing Han, Tere Williams, Yanfen Ma, Louis M. Weissa

Research output: Contribution to journalArticle

Abstract

Toxoplasma gondii causes a chronic infection that affects a significant portion of the world's population, and this latent infection is the source of reactivation of toxoplasmosis. An attribute of the slowly growing bradyzoite stage of the parasite is the formation of a cyst within infected cells, allowing the parasite to escape the host's immune response. In this study, a new bradyzoite cyst matrix antigen (MAG) was identified through a hybridoma library screen. This cyst matrix antigen, matrix antigen 2 (MAG2), contains 14 tandem repeats consisting of acidic, basic, and proline residues. Immunoblotting revealed that MAG2 migrates at a level higher than its predicted molecular weight, and computational analysis showed that the structure of MAG2 is highly disordered. Cell fractionation studies indicated that MAG2 was associated with both insoluble and soluble cyst matrix material, suggesting that it interacts with the intracyst network (ICN). Examination of the kinetics of MAG2 within the cyst matrix using fluorescence recovery after photobleaching (FRAP) demonstrated that MAG2 does not readily diffuse within the cyst matrix. Kinetic studies of MAG1 demonstrated that this protein has different diffusion kinetics in tachyzoite and bradyzoite vacuoles and that its mobility is not altered in the absence of MAG2. In addition, deletion of MAG2 does not influence growth, cystogenesis, or cyst morphology.

Original languageEnglish (US)
Article numbere00100
JournalmSphere
Volume5
Issue number1
DOIs
StatePublished - Jan 1 2020

Keywords

  • Bradyzoite
  • Cyst matrix
  • Fluorescence recovery after photobleaching (FRAP)
  • Intravacuolar network
  • Latency
  • MAG1
  • MAG2
  • Monoclonal antibody screen
  • Toxoplasma gondii

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology

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    Tu, V., Mayoral, J., Yakubu, R. R., Tomita, T., Sugi, T., Han, B., Williams, T., Ma, Y., & Weissa, L. M. (2020). MAG2, a toxoplasma gondii bradyzoite stage-specific cyst matrix protein. mSphere, 5(1), [e00100]. https://doi.org/10.1128/mSphere.0100-20