Fig. 6. Pros mutant clones phenocopy brat mutant clones in the larval central brain. Wild type (A) and pros¹⁷ MARCM clones (B-G') labelled with nuclear lacZ (A-C, white) or CD8::GFP (D,E,F,G, white) and immunostained as indicated for each panel. pros¹⁷ clones in central brain are enlarged and can cover most of the brain hemisphere (compare B with A) with multiple pros mutant clones occasionally merged into a labelled cell mass. (C-G') Close up views of labelled mutant cells reveal the presence of pleiomorphic cell types including large neuroblast-like cells (arrows) and many smaller cells (arrowheads). Brat expression is ubiquitous in larval CNS (A,B) and detected at comparable levels in cytoplasm of all mutant pros cells labelled with nuclear lacZ, or in heterozygous wild-type cells that surround labelled mutant cells (C,C'). Many pros mutant cells dispersed throughout clones are engaged in mitosis as indicated by PH3 immunoreactivity (D,D"; magenta) and most cells express CycE (D,D'; blue) and CycB (E, magenta), irrespective of their size and location within clones. Only a few nuclei are positive for the postmitotic marker Elav (F,F'; blue), whereas most cell express Mira at the cortex (F-G'; magenta) and Grh in nuclei (G,G'; blue). Cortical expression of Mira is uniform in vast majority of small cells (F-G', arrowheads), whereas polarized Mira forming crescents can be observed in large neuroblast-like cells (F-G', arrows). Scale bar, 100 µm (A,B) or 20 µm (C-G). Genotypes: (A) hsFLP/+; UAS-mCD8::GFP^LL5, UAS-nlslacZ^20b/tub-Gal4; FRT82B/FRT82B, tubP-GAL80^LL10; (B-G') hsFLP/+; UAS-mCD8::GFP^LL5, UAS-nlslacZ^20b/tub-Gal4; FRT82B, pros¹⁷/FRT82B, tubP-GAL80^LL10.