Mutant/mutation
The mutant expresses the plant auxin receptor transport inhibitor response 1 (Oryza sativa TIR1) under control of the ookinete specific soap promoter. The TIR1 is (C-terminal) tagged with FLAG 
 
Protein (function)
The plant hormone auxin induces rapid proteasomal degradation of certain proteins by a specific E3 ubiquitin ligase. To implement this system in Plasmodium, only two transgenic components are needed: a plant auxin receptor called transport inhibitor response 1 (TIR1) and a proteins of interest (POI) tagged with an AID. In these engineered parasite lines stably expressing the plant TIR1, the auxin functions as a molecular glue promoting specific interaction between the ubiquitin ligase complex and AID-tagged POI, which triggers proteasomal degradation of the latter.

Phenotype
Tir1::Flag fusion protein is highly expressed in ookinetes. Transgenic parasites showed a normal phenotype during development in blood, mosquito and liver.

Additional information
We used the CRISPR/Cas9 method to tag two genes, cdc50c (PY17X_0514500) and fbxo1 (PY17X_1120000) with the AID motif and interrogate the expression of these two proteins with auxin. The eef1a-Tir1 line allows efficient degradation of the AID-tagged endogenous protein in the asexual schizont and sexual gametocyte stages, while the soap-Tir1 line allows protein degradation in the ookinetes.
To generate the plasmid for tagging the cdc50c (PY17X_0514500) with an AID degron and sextuple HA fusing epitope (AID::6HA), the C-terminal 518 bp of coding region and 529 bp of the 3’UTR of the cdc50c gene were amplified as the homologous left and right arm, respectively. One sgRNA was designed to target the Cterminal coding region of cdc50c genes. To generate the plasmid for tagging the fbxo1 (PY17X_ 1120000) with the AID::6HA, the C-terminal 498 bp of coding region and 521 bp of the 3’UTR of the fbxo1 gene were amplified as the homologous left and right arm, respectively. One sgRNA was designed to target the C-terminal coding region of fbxo1 genes.
To assess the degradation kinetics of targeting proteins, the asexual blood stage parasites, schizonts, gametocytes, and ookinete culture were incubated with 1 or 4 mM IAA (auxin; Indole 3-acetic acid, Sigma Aldrich, I2886) at 37℃. 

We noticed that in the ookinetes of eef1a-Tir1/cdc50c::aid parasites, we failed to detect a  clear depletion of 50C-AID even after 3 hours of auxin treatment, which is likely due to the relatively lower Tir1 expression in the ookinetes compared to that in the asexual blood stage and gametocytes. Therefore, we attempted to engineer a transgenic line to achieve higher Tir1 expression in the ookinetes. To that end, we used the promoter of soap (PY17X_1040200), a gene specifically and highly expressed in the ookinetes and early oocysts, to drive the Tir1 expression. Using the CRISPR/Cas9 method, we replaced the eef1a promoter with the soap promoter (1999bp) at the upstream of Tir1 in the eef1a-Tir1 parasites (RMgm-4945), and generated a new line designated as soap-Tir1 (RMgm-4946). As expected, the Tir1 protein is highly expressed in the ookinetes, but not in the asexual blood stage of the soap-Tir1 parasites 

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