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bioRxiv · 10.1101/321786

A re-inducible genetic cascade patterns the anterior-posterior axis of insects in a threshold-free fashion

Boos, A.·Distler, J.·Rudolf, H.·Klingler, M.·El-Sherif, E.
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Abstract

Gap genes mediate the division of the anterior-posterior axis of insects into different fates through regulating downstream hox genes. Decades of tinkering the segmentation gene network of the long-germ fruit fly Drosophila melanogaster led to the conclusion that gap genes are regulated (at least initially) through a threshold-based French Flag model, guided by both anteriorly- and posteriorly-localized morphogen gradients. In this paper, we show that the expression patterns of gap genes in the intermediate-germ beetle Tribolium castaneum are mediated by a threshold-free Speed Regulation mechanism, in which the speed of a genetic cascade of gap genes is regulated by a posterior gradient of the transcription factor Caudal. We show this by re-inducing the leading gap gene (namely, hunchback) resulting in the re-induction of the gap gene cascade at arbitrary points in time. This demonstrates that the gap gene network is self-regulatory and is primarily under the control of a posterior speed regulator in Tribolium and possibly all insects.

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Boos, A., Distler, J., Rudolf, H., Klingler, M., El-Sherif, E.. 2018-05-15. A re-inducible genetic cascade patterns the anterior-posterior axis of insects in a threshold-free fashion. https://doi.org/10.1101/321786

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