Figure 1. Schematic of the siRNA screening strategy.

The work flow was organized into two rounds of screening. If both duplexes produced cilia loss and knocked down gene expression as assessed by qRT-PCR, the gene was scored as a hit. If only one duplex was effective, and only this duplex knocked down expression, a second round was pursued as indicated. All other outcomes were scored as a negative. A similar strategy was pursued for increased ciliation and, for genes whose manipulation produced this phenotype, additional analysis of ciliary length was conducted as described in the text.