Fig. 1. Specific silencing of RhoA, Rac1 and Cdc42 mediated by transient transfection of siRNA. (A) Western-blot analysis of whole-cell lysates of HSFs transfected with calcium phosphate alone (CaP), with 20 nM siRNAs targeting RhoA (siRhoA), Rac1 (siRac1) or Cdc42 (siCdc42), or with 20 nM irrelevant siRNA (siScr). 72 hours after transfection, the cells were lysed in SDS-PAGE loading buffer and analysed by immunoblotting with specific antibodies to RhoA, Rac1, Cdc42 and ERK1/2. (B) Western-blot analysis of whole-cell lysates of HSFs transfected with 20 nM siScr or with 20 nM siCdc42. Cells were lysed in SDS-PAGE loading buffer between day 1 and day 9 after transfection and analysed by immunoblotting with specific antibodies to Cdc42 and ERK1/2.