FIG. 1.
Expression of NS1 gene. (A) Induction by IPTG. Cells (2 × 105 cells/ml) were treated with the indicated concentrations of IPTG for 1 h. Total RNA from the cells was prepared, and the amount of NS1 mRNA was determined by real-time RT-PCR as described in Materials and Methods. The hatched bars indicate the copy numbers of NS1 mRNA in 1 ng of total RNA of U937/NS17 cells, and asterisks indicate the absence of NS1 mRNA in U937/CAT12 cells. (B) Kinetics of NS1 mRNA production. U937/NS17, U937/NS13, and U937/CAT12 cells were treated with 10 mM IPTG for the indicated periods of time. Total RNA from cells was prepared, and the amount of NS1 mRNA was determined as a copy number per nanogram of total RNA. The means (± standard deviations [error bars]) of three wells are shown.