Figure 3
Time-course assay of S. frugiperda heat-shock promoters in Sf9 cells. Structure of each heat-shock promoter construct is shown on the top of each panel, with a solid rectangle of light gray representing heat-shock promoter, and solid arrow of dark gray indicating the open reading frame of firefly luciferase. The approximate locations of HSEs are indicated with white vertical bars, with the numbers above representing the number of HSEs in each HSEs cluster. 100 ng of heat-shock promoter construct or pGL5luc vector was transfected into Sf9 cells. At 48 hr post-transfection, the cells were exposed to 37 °C for 1 hr, followed by recovery at 27 °C for 0, 1, 2, 4, 6, 12, and 24 hr. The cells were harvested, lysed, and the luciferase activity and protein concentration were determined. Transfected cells kept at 27 °C were used as non-heat-shock control. Numbers on the top indicate the increase in fold induction after heat-shock. Mean ± SD (n = 5) are shown. Data were analyzed using independent samples t-test built in SPSS software. *Significantly different at p < 0.05.
