Expression of
bir-1 during C. elegans development. Northern blots containing 10 μg total RNA purified from embryos (E), larval stages 1-4 (L1-L4) or adult worms (A) were probed with 32P-labelled DNA probes corresponding to the ORF of
bir-1. The positions of size markers are indicated on the left of each blot and represent the positions of rRNAs. Ethidium-bromide-stained gels with large rRNA levels as loading controls are shown below the blots.