Fig. 1. TcBR-C gene structure and mRNA expression. (A) Exons of the common core region, including the BTB domain, are spliced to one of the five zinc-finger exons (Z1-Z5). Solid and open boxes indicate coding and untranslated mRNA regions, respectively. The open reading frame is preceded by two alternative noncoding exons. The region used for whole gene silencing is shown (RNAi). Mutant line KS342 carries a piggyBac insertion 480 bp upstream of the Z1 exon. (B) Alignment of BR-C BTB domains. From top: Tribolium castaneum, Drosophila melanogaster, Aedes aegypti, Anopheles gambiae, Bombyx mori, Manduca sexta, Apis mellifera, Oncopeltus fasciatus, Acheta domesticus. (C) Total RNA from the indicated stages was subjected to DNase treatment and RT-PCR with primers for the core region or those specifically detecting the Z1-Z5 isoform transcripts. Numbers indicate hours since egg laying or ecdysis. F and M, 10-day old females and males, respectively. The prepupal stage begins at around 72 hours after the last larval ecdysis. Expression of rp49 serves for control.