ig. 2. Characterization of the designed BRET systems.
(A) Western blot analysis of protein expression for all
BRET fusions and donor-only proteins contained in
lysates of HT1080 cells stably expressing the reporter
proteins. (B) Spectral imaging of HT1080 cells expressing
either RLuc8.6 or BRET6 using 20-nm filers in the
460–720 nm range. EnduRen luciferase substrate was
used for this experiment. Error bars = SD. (C) BRET ratios
of the newly designed systems measured in cell
culture. HT1080 cells (6.4 × 104), stably expressing each
of the BRET fusion and donor-only proteins (RLuc8 or
RLuc8.6), were plated in black 96-well plates and imaged
on the addition of CLZ or CLZ-v. The graph shows
the average BRET ratios calculated as the A/D of the
BRET system minus the A/D of donor-only cells. (D) BRET
ratios calculated for the BRET6 system using various
number of HT1080 cells. Experiments were performed
as described in C. The dotted line represents the linear
fitting for the data points. Error bars = SEM.