Pair-rule genes in Drosophila integrate the positional information provided by the transcription factor gradients of gap genes and set the framework for the expression of the segment polarity genes. Pair-rule genes are also expressed during the segmentation of the short germ-band embryo of the flour beetle Tribolium, although this occurs under cellular conditions that should not allow the generation of transcription factor gradients by passive diffusion. To analyse the regulation of the pair-rule gene hairy in Tribolium, we have used germline transformation with reporter gene constructs based on the piggyBac vector. We can identify an upstream fragment that drives the full expression of the eight pair-rule stripes, which are sequentially generated during embryogenesis. Further experiments with smaller fragments reveal separable regions driving stripes three to five, and one region driving stripe three only. Our results suggest that the generation of pair-rule stripes in Tribolium is comparable to that in Drosophila despite the cellular versus syncytial mode of embryogenesis.
Short Germ-band Development
Reporter Gene Constructs