XBP1-Mediated BiP/GRP78 Upregulation Copes with Oxidative Stress in Mosquito Cells during Dengue 2 Virus Infection

Figure 4

Involvement of XBP1 in regulating BiP/GRP78 transcription in C6/36 cells with dengue 2 virus (DENV2) infection. (a) A 515 bp fragment chosen from a known sequence of XBP1 mRNA was used as the target to form a double-stranded RNA (dsRNA) segment, which was then applied to knock down the XBP1 mRNA in C6/36 cells. The results from a conventional RT-PCR showed that XBP1 mRNA was efficiently knocked down in cells transfected with dsRNA of XBP1 (relative density was close to 0 for the specific band compared to that in cells without transfecting dsRNA of XBP1). Reduced BiP/GRP78 expression was also detected in DENV2-infected cells with knockdown of XBP1 compared to control cells without treatment (relative density was shown about 0.55 compared to that in untreated cells). (b) By using a real-time PCR (RT-PCR) to quantitate the expression level of BiP/GRP78 in C6/36 cells with DENV2 infection for 24 h, its increase in multiples of change was significantly lower in C6/36 cells with knockdown of XBP1 (; Student’s -test). This indicates that XBP1 may play a role in upregulating BiP/GRP78 expression in C6/36 cells after infection with DENV2.

(a)

(b)