Fig. 4. Increased nucleolar size and rRNA level in brat/brat cells. (A) Mitotic recombination was induced with a 90 minute heat shock at 48 hours AED. At 115 hours AED, wing imaginal discs were fixed and stained with anti-Nop60B antibody. Data from two independent experiments are shown with the area of nucleoli in GFP/GFP cells set to 100 for simplicity. Mean nucleolar area is plotted with standard error indicated by error bars. The numbers of nucleoli analyzed are as follows: Experiment 1 GFP/GFP, 83; brat/brat, 47; Experiment 2 GFP/GFP, 74; brat/brat, 63. The genotype is hs-FLP¹²²; Ub-GFP FRT40A/brat¹¹ FRT40A. (B) Larvae from the cross, y; brat¹⁴/CyOY⁺ X y w; brat¹¹/CyoY⁺ were separated based on mouth hook color at 24 hours AED. When they became wandering third instars, the genotypes were confirmed and wing discs and brains were removed and processed for RNA and DNA isolation using TRIzol Reagent (Gibco BRL). Isolated RNA (standardized to isolated DNA) was applied to nitrocellulose using a slot-blot apparatus and probed with radiolabeled D. melanogaster rDNA PCR product. Quantitation was performed using a BioRad Molecular Imager FX. rRNA level in control brat/+ is set to 100 for simplicity. Average rRNA level and standard error are indicated. Ten samples of each genotype were obtained on five subsequent days; each sample consisted of 9-16 brains or 14-24 wing discs.

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