The semaphorin family comprises secreted and transmembrane proteins involved in axon guidance and cell migration. We have isolated and characterized deletion mutants of C. elegans semaphorin 1a (Ce-sema-1a or smp-1) and semaphorin 1b (Ce-sema-1b or smp-2) genes. Both mutants exhibit defects in epidermal functions. For example, the R1.a-derived ray precursor cells frequently fail to change anterior/posterior positions completely relative to their sister tail lateral epidermal precursor cell R1.p, causing ray 1 to be formed anterior to its normal position next to ray 2. The ray cells, which normally separate from the lateral tail seam cell (SET) at the end of L4 stage, remains connected to the SET cell even in adult mutant males. The ray 1 defects are partially penetrant in each single Ce-sema-1 mutant at 20°C, but are greatly enhanced in Ce-sema-1 double mutants, suggesting that Ce-Sema-1a and Ce-Sema-1b function in parallel to regulate ray 1 position. Both mutants also have defects in other aspects of epidermal functions, including head and tail epidermal morphogenesis and touch cell axon migration, whereas, smp-1 mutants alone have defects in defecation and brood size. A feature of smp-1 mutants that is shared with mutants of mab-20 (which encodes Sema-2a) is the abnormal perdurance of contacts between epidermal cells.
Semaphorin 1a and semaphorin 1b are required for correct epidermal cell positioning and adhesion during morphogenesis in C. elegans
Val E. Ginzburg, Peter J. Roy, Joseph G. Culotti; Semaphorin 1a and semaphorin 1b are required for correct epidermal cell positioning and adhesion during morphogenesis in C. elegans. Development 1 May 2002; 129 (9): 2065–2078. doi: https://doi.org/10.1242/dev.129.9.2065
Download citation file:
Sign in
Client Account
Sign in via your institution
Sign in via ShibbolethAdvertisement
Cited by
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 15 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.
In preprints
Did you know that Development publishes perspectives on recent preprints? These articles help our readers navigate the ever-growing preprint literature. Together with our preprint highlights service, preLights, these perspectives help our readers navigate the ever-growing preprint literature. We welcome proposals for ‘In preprints’ articles, so please do get in touch if you’d like to contribute.
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.