(A) wL3 brains expressing Imp::GFP and stained with myclong smFISH probes and phalloidin were used to measure Imp level, NB size, myclong transcription rate and half-life in individual NBs. MB NBs are identified by their higher Imp expression compared to type I NBs. (B–D) Each grey point represents one NB and for each NB type, brains were analysed from three experimental replicates. (B) MB NBs express higher Imp than type I NBs. The average intensity of cytoplasmic Imp signal is shown in arbitrary fluorescent units. (C) MB NBs are significantly larger than type I NBs, comparing NB area at the largest plane. (D) myc mRNA half-life is increased in MB NBs compared to type I NBs. (E) myc transcription rate is slightly lower in MB NBs than in type I NBs. (F) Plotting multiple measurements for each NB (Imp level against myc mRNA half-life, with NB size indicated by the colour scale) shows the differences between type I NBs (diamond point - low Imp, low myc mRNA stability, small) and MB NBs (circle point - high Imp, high myc mRNA stability, large). Imp level correlates with myc half-life. (G–H) Each grey point represents one brain and for each NB type, brains were analysed from three experimental replicates. (G) Myc protein is increased in MB NBs compared to type I NBs. (H) MB NBs produce more progeny in a four hour EdU incubation compared to type I NBs. Significance for each measurement was calculated using unpaired t-test, except for G) which uses a paired t-test. *p<0.01, ***p<0.001, ****p<0.0001.