Fig. 4

Expression of important transcription factors in the principal camera eyes of T. marmoratus third instars. A Relative expression of transcription factors cut (ct) and bar homolog2 (bh2) shows a tendency towards but no significant enrichment in the SupCs. Conversely, prospero (pros) shows a tendency towards but no significant enrichment in the retina. In contrast, transcription factors eyes absent (eya) and sine oculis (so) as well as the sine oculis binding protein (sobp) are significantly enriched in the SupCs. B A Cut antibody (green), which is known to mark Semper cells in the compound eyes of T. marmoratus adults stains a subset of SupCs (cyan, arrow) in a section that is counter-stained with DAPI (blue) [8], stained a specific subset of proximally placed SupCs (teal, arrows), scale bar = 100 µm. See SupFig1 for separate channels of the staining. C As illustrated by the schematic, the staining pattern supports the deep conservation of this transcription factor and is consistent with our model, in which a portion of the SupCs in T. marmoratus larval eye tubes (green) are homologous to D. melanogaster Semper cells