Figure 1.

Loss of dFmr1 alters cell cycle progression in the larval brain. (A–F) Staining for the M-phase marker PH3 in wild-type (A) and dFmr1³ mutant (B) larval brains. Dashed lines delineate the CB areas. The stem cell-specific protein Miranda marks NBs (C–F). Higher magnification indicates that the dFmr1 mutant brains contain more PH3 positive neuroblasts (F, arrowheads) compared with wild-type (E, arrowheads). (K) Total number of mitotic neuroblasts (NBs) are significantly increased in both dFmr1³ homozygotes (P = 0.04) and dFmr1³/50M (P < 0.001) brains compared with the genetic rescue, P[dFmr1];dFmr1³. There is no statistical significance (n.s.) between the w¹¹¹⁸ and genomic rescue controls. Student's t-test was used to calculate statistical significance. (G–J) Staining for the S-phase marker BrdU in wild-type (G and I) and dFmr1 mutant (H and J) larval brains. The cortical protein Lgl was used to delineate the CB (see also dashed areas) region, where the neuroblasts and associated cells display higher levels of BrdU incorporation in dFmr1 mutants (H and J) compared with wild-type (G and I). Stainings and genotypes as indicated. Brains were dissected from age matched late third instar larvae. Scale bar in (A) 120 µm, in (E) 30 µm. All images are projections of three confocal slices, slice size = 2 µm.