Silenced genes in Cryptosporidium. A, Quantitative polymerase chain reaction (qPCR; top) shows a fold reduction in messenger RNA target from transfected parasites with human Argonaute 2 (hAgo2) loaded with single-stranded RNA (ssRNA) specific for glycoprotein (Gp900; black bar). Control parasites were treated only with transfection reagent (wild type [WT]). Western blot analysis of Gp900 (bottom) in parasites transfected (ssRNA Gp900) or not transfected (WT control). B, qPCR analysis was used to calculate the percentage reduction in expression, relative to basal expression, for the Cryptosporidium targets Cp15, glycoprotein (Gp900), calcium-dependent kinase 1 (CDPK), inosine-5-monophosphate dehydrogenase (Ino-5mon), and Cp17 (gray bars). C, Transfected parasites were used to evaluate the role of silenced genes during infection. Percentages are relative to control (parasites were transfected only with protein transfection reagent [PTR]). In panels B and C, data are mean ± SD of qPCR triplicates and are representative of at least 3 individual experiments with similar results.