Genome-wide mapping of transcription initiation in the asexual stages of Toxoplasma gondii

The lack of a comprehensive map of transcription start sites in Toxoplasma gondii has impeded advances in decrypting the molecular mechanisms underlying the regulation of gene expression. Genome-wide approaches for mapping transcription initiation have been instrumental in defining the determinants of transcription initiation in a range of model eukaryotes. We used a protocol for 5′-end RNA sequencing, called RAMPAGE, to sequence the 5′-ends of capped mRNA from ME49 and RH tachyzoites, as well as from ME49 bradyzoites. This allowed us to generate maps of transcription initiation events at single-nucleotide resolution across the asexual stages of the parasite. Examination of the 5′-ends of capped mRNA in ME49 tachyzoites and alkaline-stress–induced bradyzoites, as well as in RH tachyzoites; each evaluated in two biological replicates.