In dicotyledonous plants, the apical region of the embryo shifts from radial to bilateral symmetry as the two cotyledon primordia develop on opposite sides of the shoot meristem. To further elucidate the mechanisms regulating this patterning process, we analyzed functions of two Arabidopsis genes, PIN-FORMED1 (PIN1) and MONOPTEROS (MP), encoding a putative auxin efflux carrier and a transcription factor thought to mediate auxin signaling, respectively. The corresponding mutants show similar defects in apical patterning, including cotyledon fusion and dissymmetric organ positioning. Both mutations perturb the spatial expression patterns of CUP-SHAPED COTYLEDON1 (CUC1) and CUC2, which are redundantly required for cotyledon separation and meristem formation. During early embryogenesis, both CUC genes are affected differently: the area of CUC1 expression is expanded while that of CUC2 expression is reduced. In addition, genetic analysis indicates that PIN1 and MP are required for the activity of CUC2 while CUC1 activity is only slightly affected by both mutations. These results suggest a differential regulation of the CUC genes by PIN1 and MP. Furthermore, genetic analysis suggests that SHOOT MERISTEMLESS (STM), another regulator for cotyledon separation and meristem formation, promotes CUC1 activity in parallel with PIN1. Our results suggest a model where PIN1 and MP regulate apical patterning partially through the control of CUC gene expression.
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 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.
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