RNA triphosphatase-mediated mRNA capping is essential for maintaining transcript homeostasis and the survival of Toxoplasma gondii.

ABSTRACT: RNA modifications are crucial for gene expression in eukaryotes; however, the regulatory role of 5' 7-methylguanosine (m⁷G) cap, the first modification of mRNA, remains unknown in the protozoan parasite Toxoplasma gondii. Here, we show that the mRNA capping machinery of Toxoplasma consists of three distinct enzymes: RNA triphosphatase, guanylyltransferase, and guanine-N7-methyltransferase, which together add m⁷G cap to RNA, recognized by cap-binding protein, TgeIF4E. Biochemical and genetic studies show that among three capping enzymes, RNA triphosphatase (TgCet) is unique and a member of the tunnel family of metal-dependent phosphohydrolases, which is structurally and mechanistically distinct from the human RNA triphosphatase. Using conditional knockdown, we show tha

SUBMITTER: Aswale KR 

PROVIDER: S-EPMC12215270 | biostudies-literature | 2025 Jul

REPOSITORIES: biostudies-literature