Tachyzoites of the
T. gondii cKD
TgAtg8 cell line (12 (
link)), as well as derived transgenic parasites generated in this study, were maintained by serial passage in a human foreskin fibroblast (HFF; American Type Culture Collection; CRL 1634) cell monolayer grown in Dulbecco’s modified Eagle’s medium (DMEM; Gibco), supplemented with 5% decomplemented fetal bovine serum, 2-mM
l-glutamine, and a cocktail of penicillin-streptomycin at 100 μg/mL.
Complemented cell lines were generated by insertion of an additional
TgAtg8 copy at the uracil phosphoribosyltransferase (UPRT) locus in the cKD
TgAtg8 mutant (12 (
link)). The pGFP-
TgAtg8 plasmid (64 (
link)) was used as a template with primers ML2463 and ML2464, and the products were self-ligated to generate p-GFP-TgAtg8Δ68-76 excluding amino acids 68 to 76 (
QCAQNSGLP). A 1.5-kbp sequence corresponding to the promoter region of
TgAtg8 was obtained by PCR from genomic DNA with primers ML2429 and ML2430 and cloned with NsiI upstream of the GFP-
TgAtg8 or GFP-
TgAtg8ΔLoop fragment in its respective plasmid. These were then used as a PCR template to amplify, with primers ML2624 and ML2625, a cassette containing the
TgAtg8 promoter followed by the sequence coding for GFP-fused wild-type (WT) or truncated
TgAtg8. These cassettes were cloned using NotI and XmaI into the pUPRT-TUB-Ty plasmid (65 (
link)) to yield the pUPRT-GFP-
TgAtg8 and pUPRT-GFP-
TgAtg8ΔLoop plasmids, respectively. These plasmids were then linearized with KpnI and BamHI prior to transfection into the cKD
TgAtg8 cell line (12 (
link)) together with a plasmid expressing Cas9 and a UPRT-specific guide RNA under the control of a U6 promoter (66 (
link)). Then transgenic parasites were selected with 5 μM fluorodeoxyuridine and cloned by limiting dilution. Primers are listed in
Table S1.
Walczak M., Meister T.R., Nguyen H.M., Zhu Y., Besteiro S, & Yeh E. (2023). Structure-Function Relationship for a Divergent Atg8 Protein Required for a Nonautophagic Function in Apicomplexan Parasites. mBio, 14(1), e03642-21.