Figure 4

Influence of incubation times at 4°C on the level of bimolecular fluorescence complementation (BiFC) signals and embryonic lethality. (a) Influence of various incubation times on the level of BiFC signals. BiFC resulted from the expression of the VCA and VNE fusion proteins with the abdA-Gal4 driver. Confocal images of stage 10 embryos were taken under same parameters of acquisition after various periods of incubation at 4°C, as indicated. (b) Statistical representation of the effect of incubation times on the embryonic lethality (black curve) and on BiFC levels resulting from the VCA/VNE assembly (green curve) or from VN/VC interactions (dotted-green curve, not quantified with regard to VCA/VNE, as symbolised by double lines). An incubation time of 28 h (highlighted in red) was considered as best appropriate for visualizing BiFC with fusion proteins (with a corresponding low rate of lethality and high level of fluorescence). This time was systematically applied for BiFC observations described in the following figures. See also Material and Methods.