Fig. 2. Loss of TcBR-C blocks Tribolium metamorphosis. (A) A control pupa shows developed and elongated wings (black arrows), legs (white arrow) and gin traps (open arrowheads). (B) A prepupa that had been injected with the common-region TcBR-C dsRNA as a fifth-instar larva developed normally until it died at the end of the final instar. Upon removal of the apolysed larval cuticle the same animal displayed larval shape and rudimentary wings (B', black arrows). (C-G) Essentially the same phenotype was found in dying animals homozygous for the KS342 piggyBac insertion that were freed from the larval cuticle. Note the vestigial wings and short legs (black and white arrows, respectively), defects in compound eyes (black arrowheads), thick antenna (asterisk), short larval urogomphi (F, ur) and missing gin traps (G) above abdominal spiracles (sp). (H) Total RNA from wild-type prepupae and from two sets of arrested TcBR-C^KS342 homozygous prepupae (two per sample) was subjected to RT-PCR. Note the reduced Z2 and Z3 mRNA levels in TcBR-C^KS342. Expression of rp49 served as a control. (I) Lower doses of the common-region TcBR-C dsRNA allowed ecdysis into imperfect pupae with more developed yet abnormally short wings (black arrows in A through D), partially formed gin traps (white arrowheads), and short legs (white arrow). In B' and C, larval cuticle could not be completely removed from the anterior head and distal legs. Scale bars: in A,1 mm for A-B',I; C, 1 mm; D,F, 500 µm; E,G, 200 µm.