Figure 6. Precocious transcriptional repression of endogenous βFTZ-F1 is sufficient to accelerate developmental timing.

(A) Endogenous βFTZ-F1 regresses significantly faster after expression of βFTZ-F1 protein from a heterologous promoter (hs-βFTZ-F1). All genotypes have similar levels of induction of endogenous βFTZ-F1 at 0.5 hrs after heat shock (AHS). Ectopic βFTZ-F1 protein shuts off endogenous βFTZ-F1 transcription by 3.5 AHS in control animals (dashed black line), but it takes longer in ino80^psg25 mutant animals (dashed blue line). y-axis plots relative expression compared the lowest point in the developmental profile; x-axis represents hours after heat-shock (AHS). Three independently-isolated whole animal samples were run for each timepoint and normalized to rp49. (B) Accelerated repression of βFTZ-F1 is sufficient to decrease the duration of prepupal development. 50% of heat-shocked control animals head evert by 12.75 APF (HE₅₀∼12.5 APF, total n=104). However, additional βFTZ-F1 protein accelerates the timing of head eversion by 2 hours (dashed black line, HE₅₀∼10.75 APF, total n=101). 50% of heat-shocked ino80^psg25 mutants head evert by 14.25 APF (solid blue line, HE₅₀∼14.25 APF, total n=97), but ectopic expression of βFTZ-F1 protein in the ino80^psg25 mutant background accelerates the timing of head eversion by about 2 hours (dashed blue line, HE₅₀∼12.25 APF, total n=99). x-axis represents hours after puparium formation (APF); y-axis represents the percentage of animals head everted. Three independent samples of n∼33 animals were analyzed for each genotype; error bars represent plus or minus one standard deviation. Triangles denote time of heat-shock in each genotype (black=control; blue=ino80^psg25/Df).