Abstract
Segmentation genes in insects are required for generating the subdivisions of the early embryo. We describe here a new member of the gap family of segmentation genes in the flour beetle
Tribolium,
mille-pattes (
mlpt).
mlpt knockdown leads to transformation of the abdominal segments into thoracic segments, providing embryos with up to ten pairs of legs. We show that there are crossregulatory interactions between
mlpt and the known gap genes in
Tribolium, suggesting that
mlpt is itself a gap gene. The
mlpt gene reveals an unusual structure, as it encodes a polycistronic mRNA that codes for four peptides.
mlpt appears to be the prototype of this previously unknown gene structure in eukaryotes, as we find homologous genes with the same polycistronic arrangement in other insect genomes as well.