PMC

A schematic diagram of a third instar eye-antennal imaginal disc. Nearly all retinal determination genes, including Tsh and Tio, can convert a population of cells (labeled in red, arrowhead) lying within the ventral most section of the antenna. Both genes, in addition to dan and danr, are also able to transform a second population of cells (labeled in pink, arrow).

(A) Schematic diagram of Tsh and Tio proteins. (B) Confocal images of third instar imaginal discs. Both discs are of wild type animals. Anterior is to the right and the visualized molecules are listed at the bottom right of each panel. (C) Determination of tsh and tio transcript levels in the developing eye imaginal disc using quantitative RT-PCR.

(A-H). Confocal images of third instar imaginal discs. The identity of the GAL4 driver is listed at the bottom right of each panel. All lines were crossed to a UAS-GFP responder. F-actin is visualized in red while GFP is visualized in blue. Anterior is to the right. (I) A table describing the average copy number of GAL4 transcripts for each driver line. (J). Determination of GAL4 transcript levels in the developing eye-antennal disc of different GAL4 lines using quantitative RT-PCR.

(A, C) SEM of adult compound eyes. Genotype is listed at the bottom right of each panel. Anterior is to the right. (B, D) Determination of the tsh and tio transcript levels in the developing eye-antennal discs. Note that these quantifications include both endogenous and exogenous transcript levels. (E) Determination of tsh and tio transcript levels that are just derived from GMR-GAL4 over expression. The endogenous wild type values were subtracted from the total values in panels B and D.

(A-E) Confocal images of third instar imaginal discs. The identity of the GAL4 driver is listed at the bottom right of each panel. All lines were crossed to a UAS-tsh responder. Visualized molecules are listed in the top right of each panel. Green arrows and arrowheads denote the two cell populations that can be converted into developing photoreceptors. White arrow denotes area where a new morphogenetic furrow is observed. Pink arrow indicates areas where there is no new furrow. Anterior is to the right. (G, H) Light microscope images of adult animals. The identity of the GAL4 driver is listed at the bottom right of each panel. Both lines were crossed to a UAS-tsh responder. Anterior is to the left.

(A-G) Confocal images of third instar imaginal discs. The identity of the GAL4 driver is listed at the bottom right of each panel. All lines were crossed to a UAS-tio responder. Please note that we were unable to detect ELAV positive cells within the antennal disc of animals in which UAS-tio was expressed by the T98-GAL4 line (despite the fact that we see ectopic eyes in the adult). The final stages of photoreceptor development likely take place during the pupal stage. Visualized molecules are listed in the top right of each panel. Green arrows and arrowheads denote the two cell populations that can be converted into developing photoreceptors. White arrow marks a morphogenetic furrow that extends along the entire length of the internal edge of an ectopic eye. Anterior is to the right.