Fig. 5. larval brat mutant central brain clones continue to proliferate into adulthood. (A-D) Dissected whole-mount 3-week-old adult brains showing MARCM clones which had been induced in early first instar larvae. (A) X-gal detection of nuclear lacZ marker (blue) reveals typical sizes of wild-type MARCM clones in central brain (arrowhead) and optic lobe (arrow). (B) Close up view of wild-type clones in central brain immunostained with anti-ß-galactosidase (nuclei, white). Wild-type clones lack PH3 immunoreactivity (magenta) consistent with proliferation arrest during puparium formation and metamorphosis. (C) X-gal labelled brat¹¹ MARCM clones in central brain (arrowheads) are dramatically enlarged in size, whereas mutant clones in optic lobe (arrows) appear wild-type-like. [The brown axon-like structures on the specimen (asterisks) are the remains of the adult head cuticule.] (D) Double-immunolabelling of nuclear ß-gal (white) and PH3 (magenta) reveals numerous cells of the enormously enlarged brat mutant clones mitotically active even 3 weeks after adult eclosion (compare with B). Scale bars, 50 µm; genotypes as in Fig. 2.