TY - JOUR TI - Dynamic BMP signaling polarized by Toll patterns the dorsoventral axis in a hemimetabolous insect AU - Sachs, Lena AU - Chen, Yen-Ta AU - Drechsler, Axel AU - Lynch, Jeremy A AU - Panfilio, Kristen A AU - Lässig, Michael AU - Berg, Johannes AU - Roth, Siegfried A2 - Barkai, Naama VL - 4 PY - 2015 DA - 2015/05/12 SP - e05502 C1 - eLife 2015;4:e05502 DO - 10.7554/eLife.05502 UR - https://doi.org/10.7554/eLife.05502 AB - Toll-dependent patterning of the dorsoventral axis in Drosophila represents one of the best understood gene regulatory networks. However, its evolutionary origin has remained elusive. Outside the insects Toll is not known for a patterning function, but rather for a role in pathogen defense. Here, we show that in the milkweed bug Oncopeltus fasciatus, whose lineage split from Drosophila's more than 350 million years ago, Toll is only required to polarize a dynamic BMP signaling network. A theoretical model reveals that this network has self-regulatory properties and that shallow Toll signaling gradients are sufficient to initiate axis formation. Such gradients can account for the experimentally observed twinning of insect embryos upon egg fragmentation and might have evolved from a state of uniform Toll activity associated with protecting insect eggs against pathogens. KW - Tribolium KW - Oncopeltus KW - Nasonia KW - axis formation KW - pattern formation KW - gene regulatory network JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -