Fig. 4.

Knockdown of oatp58Db by RNAi reduces active ouabain transport. (A) Western blot analysis of oatp 58Db expression in RNAi tubules. Tubules were dissected from lines containing a principal cell-specific GAL4 driver (c42), the RNAi construct under UAS control (58Db-RNAi), or both (58Db-RNAi/c42). Only in this last case, RNAi should be activated in the principal cells. (Left) Blot probed with α-oatp58Db. (Right) Blot stripped and reprobed with α-Na, K ATPase, as a loading control, and to verify the specificity of RNAi action. Arrows denote the predicted sizes of each protein. (B) RNAi to oatp58Db reduces active uptake of ouabain by around 50%. Tubules were dissected from parental lines as described in A, and assayed for ouabain transport as described. (data as mean ± SEM, n = 7.)