Axon guidance defects in <i>Tsc1</i> mosaics are not suppressed by blocking growth.

<p>(A–C) Third instar eye discs from wild type and <i>Tsc1</i> mosaic larvae raised with or without rapamycin (rap). Ommatidial units, comprised of eight photoreceptors, were visualized with phalloidin (red) that detects F-actin, and MAb24B10 (green). Phalloidin staining is strongest at the perimeter of each ommatidium, outlining each sensory unit. Rapamycin treatment of <i>Tsc1</i> mosaic eye discs (C) restored eye disk size and cell size compared to wild type (A). (D and E) Rapamycin treated third instar larval brains stained with MAb24B10. Rapamycin treatment blocked abnormal growth of the retina and the increase in photoreceptor cell size, but did not ameliorate the abnormal axon projections also characteristic to untreated <i>Tsc1²⁹</i> mosaics. The scale bars in panel A represent 50 microns in the left image, 10 microns in the right image. The scale bar is 50 microns in panel D.