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Developmental Biology

Anne Ephrussi

Anne Ephrussi
Head of Developmental Biology Unit

The development of living organisms requires precise coordination of all basic cellular processes, in space and time. Groups seek to elucidate the principles, mechanisms and dynamics of fundamental developmental events. Using animal and plant models, research in the Unit integrates numerous complementary approaches to understand how cellular and morphological processes are coordinated and evolve to shape and maintain living organisms in their environment.

A fundamental question in developmental biology is the mechanism by which symmetry is broken and cells with distinct fates are specified. Researchers in the Unit are studying a number of related research areas, including the mechanisms underlying cell polarisation, mRNA transport, and translational control in Drosophila; how auxin specifies different cell types in Arabidopsis; and a systemslevel understanding of the symmetry breaking processes operating in the early mouse embryo.

During development, progenitor cells divide and differentiate into tissues of characteristic shape and function. Another aim is to elucidate how cells in the early Drosophila embryo reorganise their content in response to the expression of key developmental transcription factors and, specifically, how tissue-specific gene expression controls protein and membrane trafficking, and how this trafficking regulates cell fate and behaviour.

Overview on Research in the Developmental Biology Unit

Arendt Group Evolution of the central nervous system in bilateria
Aulehla Group Timing of mammalian embryogenesis
De Renzis Group Cell dynamics and signalling during morphogenesis
Ephrussi Group RNA localisation and regulaiton in development
Heisler Group Developmental patterning in plants
Hiiragi Group Systems-level understanding of early mammalian development
Peri Group Microglia: the guardians of the developing brain
Spitz Group Gene regulation and genome architecture

Elucidating the temporal organisation of embryonic development is a further goal. Using the mouse model, the mechanisms controlling overall developmental rate at an organismal level, as well as the timing of individual patterning processes and the dynamics of underlying signalling pathways, are being investigated. Analysis of novel mouse reporter lines using real-time imaging techniques allows visualisation of the activity and dynamics of signalling pathways in the context of a developing embryo.

The marine annelid Platynereis is an ideal model for exploring the evolution of cell types. Large-scale expression profiling at cellular resolution has revealed the evolutionary origin of the vertebrate hypothalamus. Using this model, research in the Unit aims at solving one of the major remaining mysteries in animal evolution: the evolution of the central nervous system.

Several groups seek to understand both normal development and its deviations in disease. During brain development, vast numbers of neurons are targeted for death and are cleared rapidly and efficiently by a resident lineage of phagocytes, the microglia. Combining live imaging and genetic approaches, the dynamic relationship between neurons and microglia in zebrafish is actively investigated.

Re-shuffling of regulatory inputs after chromosomal rearrangements is the likely cause of several human genetic disorders. Focusing on the regulatory architecture of key developmental loci, another goal in the Unit is to understand the molecular mechanisms that control functional interactions between genes and remote cis-regulatory elements, and to determine how they contribute to phenotypic variations during vertebrate evolution and in humans.

Anne Ephrussi
Head of the Developmental Biology Unit