Fig. 6. Loss of DSec61α causes induction of UPR. (A) Drosophila S2 cells were tranfected with dsRNA (80 ng of each EGFP and DSec61α), and incubated for 24 h. The UPR induction at each time point (3, 6, 12, and 24 h) was measured as described below. Briefly, total RNAs were extracted from S2 cells and subjected to quantitative RT-PCR with a Drosophila BiP (dBiP)-specific probe and primers. mRNA level of each sample was normalized by Drosophila glyceraldehyde-3-phosphate dehydrogenase (dG3PDH) level. The relative amounts of dBiP/dG3PDH represent the percentage increase compared with the amount obtained from no treatment. The error bars represent the SD calculated from triplicate samples. Please note that the transient induction of UPR was observed in DSec61α knockdown cells. (B) Drosophila S2 cells were tranfected with dsRNA (50, 100, and 200 ng of each EGFP and DSec61α) or treated with tunicamycin (5 mg/ml), and incubated for 24 h. The WT (w¹¹¹⁸) and DSec61α mutant embryos with indicated genotypes were collected at after egg laying 12-16 h. Please note that the severe induction of UPR was observed in strong mutant of DSec61α (DSec61α^P560/DSec61α^P560). The UPR induction was measured as described in A.