Dorsoventral polarity of the Drosophila embryo requires maternalspätzle-Toll signaling to establish a nuclear gradient of Dorsal protein. The shape of this gradient is altered in embryos produced by females carrying dominant alleles of easter (eaD). Theeaster gene encodes a serine protease that generates processed Spätzle, which is proposed to act as the Toll ligand. By examining the expression domains of the zygotic genes zen, sog, rho andtwist, which are targets of nuclear Dorsal, we show that the slope of the Dorsal gradient is progressively flattened in strongereaD alleles. In the wild-type embryo, activated Easter is found in a high Mr complex called Ea-X, which is hypothesized to contain a protease inhibitor. In eaDembryo extracts, we detect an Easter form corresponding to the free catalytic domain, which is never observed in wild type. These mutanteaD proteins retain protease activity, as determined by the production of processed Spätzle both in the embryo and in culturedDrosophila cells. These experiments suggest that theeaD mutations interfere with inactivation of catalytic Easter, and imply that this negative regulation is essential for generating the wild-type shape of the Dorsal gradient.
Interviews with Biologists @ 100 conference speakers
Explore our interviews with keynote speakers from the Biologists @ 100 conference, hosted to celebrate our publisher’s 100th anniversary, where we discuss climate change and biodiversity with Hans-Otto Pörtner and Jane Francis, health and disease with Charles Swanton and Sadaf Farooqi, and emerging technologies with Manu Prakash and Jennifer Lippincott-Schwartz.
Call for papers – Lifelong Development: the Maintenance, Regeneration and Plasticity of Tissues
Development invites you to submit your latest research to our upcoming special issue – Lifelong Development: the Maintenance, Regeneration and Plasticity of Tissues. This issue will be coordinated by Guest Editors Meritxell Huch (Max Planck Institute of Molecular Cell Biology and Genetics, Germany) and Mansi Srivastava (Harvard University and Museum of Comparative Zoology, USA), working alongside our team of academic Editors. Submit your articles by 30 May 2025.
A case for broadening our view of mechanism in developmental biology
In this Perspective, B. Duygu Özpolat and colleagues survey researchers on their views on what it takes to infer mechanism in developmental biology. They examine what factors shape our idea of what we mean by ‘mechanism’ and suggest a path forward that embraces a broad outlook on the diversity of studies that advance knowledge in our field.
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