Common Transcriptional Mechanisms for Visual Photoreceptor Cell Differentiation among Pancrustaceans
Figure 10
Knockdown of Tribolium Pph13, otd1 and otd2 affects rhabdomere biogenesis.
Scanning and transmission electron microscopy analyses of Tribolium adult eyes. A,F. Mock injection. B,G. Pph13 RNAi. C,H. otd1 RNAi. D,I. otd2 RNAi. E,J. otd1 and otd2 RNAi. The green shading marks the cell body of one of the eight photoreceptors (PC) found in each ommatidium. Each photoreceptor produces a rhabdomere (R1–R8) that remains juxtaposed to the others. The knockdown of Pph13 and orthodenticle paralogs did not affect the overall structure of the adult eye (A–E). However, the knockdown of Pph13 (G) and the combinatorial removal of both otd paralogs result in a complete absence of rhabdomeres (J). Photoreceptors are detected but the microvillar rhabdomere structures are absent. The knockdown of otd1 generates smaller rhabdomeres (H) and the removal of otd2 (I) alone results in rhabdomeres in an active state of degeneration (arrow).