Fig. 4. Depletion of PCTAIRE-1 expression using RNAi causes disruption of morphology of the early secretory pathway. HeLa cells were transfected with siRNA duplexes targeting lamin or PCTAIRE-1. After 72 hours, cells were lysed and blotted for PCTAIRE-1 (A) or lamin (B). (C) Cells grown on coverslips, transfected with siRNA specific for PCTAIRE-1 and incubated for 72 hours. Cells were then fixed and processed for immunofluorescence with antibodies specific to GM130, ERGIC-53, Sec24Dp, giantin, -tubulin or the KDEL-receptor. (D) Enlargement of the boxed regions of ERGIC-53 immunolabelling (green) from C show that PCTAIRE-1 siRNA results in increases ER labelling clearly shown by the nuclear envelope localization. The nucleus (DNA labelled with DAPI) is shown in blue.