GSE134099
Temporal analysis of in vivo Toxoplasma gondii cysts shows novel and late stage specific transcripts.
The protozoan pathogen Toxoplasma gondii has the unique ability to develop a chronic infection in the brain of its host. The T. gondii develops cysts within the neurons that are resilient against the host immune response and current therapeutics. The bradyzoite parasites within the cyst have a sugar-protein-rich wall and a slow-replication cycle, allowing them to remain hidden from the host. This intracellular encysted lifestyle of T. gondii has made them recalcitrant to molecular analysis in vivo. Here, we have enriched for T. gondii brain cysts 21 to 150 days post-infection (DPI). RNA and protein from bradyzoites was isolated from each timepoint. Deep sequencing of transcripts expressed during these three timepoints showed many of the identified proteins are transcriptionally expressed at a high level. Approximately one-third are more enriched during bradyzoite conditions compared to tachyzoites, and approximately half are expressed at similar levels during each phase. We have expanded the transcriptional profile of in vivo bradyzoites to 120 DPI. The RNA sequencing depth of in vivo bradyzoite T. gondii was over 250-fold greater than was have been previously, which allowed us to identify low level transcripts and novel bradyzoite-specific isoforms. Overall design: Illumina sequecing of bradyzoites isolated from mouse brain cysts, 28, 90, and 120 days postinfection in duplicate. Sequencing ran on two lanes and collated together.