FIG. 1.

Targeted disruption of four serine-type SERA genes. (A) Schematic representation detailing the outcome of expected integration events in SERA knockout parasite lines. Solid lines under the exons represent the location of the gene targeting regions used to clone fragments into pHH1 (SERA1), pTKΔSERA4, pTKΔSERA5, and pTKΔSERA9. The targeting regions of the coding sequence are indicated by the gray shaded regions. (B) Southern blots summarizing the result of the attempted targeted disruption of each SERA gene using restriction-digested genomic DNA from each transfected line following drug cycling and parental parasites. Genomic DNA was digested BstBI (B)/SphI (S) for SERA1, AflIII (A) for SERA4, XmnI (X) for SERA5, and BclI (Bc)/NotI/SwaI (Sw) for SERA9. The membranes were probed with each respective targeting sequence shown above (A). The positions of endogenous (E), plasmid (P), and integration-specific fragment (In) events that result from digestion with the respective enzymes and the probing of blots with the specific targeting region (gray) are indicated, and their molecular weights (in thousands) are given below each relevant blot. RE, restriction enzyme.