Hedgehog (Hh) signalling is essential for the development of many vertebrate epidermal appendages, including hair and teeth. Another epidermal appendage that shares a common origin is the mammary gland. But, as Hatsell and Cowin now report, positive Hh signalling is absent throughout the embryonic and postnatal development of mouse mammary glands (see p. 3661). In mammals,three Gli transcription factors act downstream of Hh: the activator Gli2 induces the expression of Gli1, which antagonizes the repressor activity of Gli3. The researchers show that although Gli2 and Gli3 are expressed during embryonic mammary development, Hh target genes are not expressed. Furthermore, whereas mammary gland development is normal in mice that lack Gli1 or Gli2, two pairs of mammary buds are missing in Gli3xt/xt mouse embryos, which do not make Gli3. Misactivation of the Hh pathway by targeted expression of Gli1in Gli3xt/+ mice also induces mammary bud loss....
The Company of Biologists Workshops
For the last 15 years, our publisher, The Company of Biologists, has provided an apt environment to inspire biology and support biologists through our Workshops series. Read about the evolution of the Workshop series and revisit JEB's experience with hosting the first Global South Workshop.
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.
Meet our 2025 Pathway to Independence (PI) fellows
We are delighted to announce our third cohort of PI fellows - researchers whom we will be supporting as they transition from postdoc to Principal Investigator. Read about the eight talented fellows chosen, whom we're excited to be working with as they navigate the job market.
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.
the Node: Have your say
Our community site, the Node, is conducting a user survey about the content and the design of the site. Help us shape the Node's future and thank you for being a part of the Node over the last 15 years.
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