Figure 4

Cropped controls the sizes of organs and individual cells and not cell number in larvae. (A) The cropped transgene was expressed at high levels with A9-Gal4 driver in many tissues in L3 larvae. The protein level of Cropped in the salivary gland (A) and nerve cord and imaginal discs (B) was visualized with the brown stain from horseradish peroxidase bound to the secondary antibody. The salivary glands from WT (C) and A9-Gal4 overexpressing the cropped transgene (D) were dissected from the larvae. The central nervous system from WT (E) and overexpressing the cropped transgene (F) were also removed from the larvae for size comparison. The photomicrographs were taken with the same power of magnification, and the pictures on the right were using dark-field microscopy. (G) The length and width of the salivary glands, brain lobes, and ventral nerve cord were measured. The blue bars were the measurements from WT larvae, and the red bars were from Cropped-overexpressing larvae. The errors above the bars were SEM. The scale bar = 150 μm from A to F. From H to M, the salivary glands and fat body from both WT (H-J) and A9-Gal4 overexpressing cropped (K-M) were stained with DAPI to identify the nuclei of the cells. The cells of the salivary glands from WT larvae (H and I) and from Cropped-overexpressing larvae (K and L) are shown under DIC optics (H and K) and DAPI-stained (I and K). J and M are photomicrographs of DAPI-stained fat body cells. From H to K, the photographs were taken with the same magnification, and the scale bar indicates 60 μm. (N) The quantitation of the number of nuclei from the salivary glands of the two types of larvae.