Saturday, March 21, 2015

Yeast Three-Hybrid Screen Identifies TgBRADIN/GRA24 as a Negative Regulator of Toxoplasma gondii Bradyzoite Differentiation

 2015 Mar 19;10(3):e0120331. doi: 10.1371/journal.pone.0120331. eCollection 2015.

Abstract

Differentiation of the protozoan parasite Toxoplasma gondii into its latent bradyzoite stage is a key event in the parasite's life cycle. Compound 2 is an imidazopyridine that was previously shown to inhibit the parasite lytic cycle, in part through inhibition of parasite cGMP-dependent protein kinase. We show here that Compound 2 can also enhance parasite differentiation, and we use yeast three-hybrid analysis to identify TgBRADIN/GRA24 as a parasite protein that interacts directly or indirectly with the compound. Disruption of the TgBRADIN/GRA24 gene leads to enhanced differentiation of the parasite, and the TgBRADIN/GRA24 knockout parasites show decreased susceptibility to the differentiation-enhancing effects of Compound 2. This study represents the first use of yeast three-hybrid analysis to study small-molecule mechanism of action in any pathogenic microorganism, and it identifies a previously unrecognized inhibitor of differentiation in T. gondii. A better understanding of the proteins and mechanisms regulating T. gondii differentiation will enable new approaches to preventing the establishment of chronic infection in this important human pathogen. 
PMID:
 
25789621
 
[PubMed - in process] 

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