A positive feedback loop controls Toxoplasma chronic differentiation

M. Haley Licon, Christopher J. Giuliano, Alex W. Chan, Sundeep Chakladar, Julia N. Eberhard, Lindsey A. Shallberg, Sambamurthy Chandrasekaran, Benjamin S. Waldman, Anita A. Koshy, Christopher A. Hunter, Sebastian Lourido

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


Successful infection strategies must balance pathogen amplification and persistence. In the obligate intracellular parasite Toxoplasma gondii this is accomplished through differentiation into dedicated cyst-forming chronic stages that avoid clearance by the host immune system. The transcription factor BFD1 is both necessary and sufficient for stage conversion; however, its regulation is not understood. In this study we examine five factors that are transcriptionally activated by BFD1. One of these is a cytosolic RNA-binding protein of the CCCH-type zinc-finger family, which we name bradyzoite formation deficient 2 (BFD2). Parasites lacking BFD2 fail to induce BFD1 and are consequently unable to fully differentiate in culture or in mice. BFD2 interacts with the BFD1 transcript under stress, and deletion of BFD2 reduces BFD1 protein levels but not messenger RNA abundance. The reciprocal effects on BFD2 transcription and BFD1 translation outline a positive feedback loop that enforces the chronic-stage gene-expression programme. Thus, our findings help explain how parasites both initiate and commit to chronic differentiation. This work provides new mechanistic insight into the regulation of T. gondii persistence, and can be exploited in the design of strategies to prevent and treat these key reservoirs of human infection.

Original languageEnglish (US)
Pages (from-to)889-904
Number of pages16
JournalNature Microbiology
Issue number5
StatePublished - May 2023

ASJC Scopus subject areas

  • Microbiology
  • Immunology
  • Applied Microbiology and Biotechnology
  • Genetics
  • Microbiology (medical)
  • Cell Biology


Dive into the research topics of 'A positive feedback loop controls Toxoplasma chronic differentiation'. Together they form a unique fingerprint.

Cite this