The International Journal of Developmental Biology

Int. J. Dev. Biol. 58: 9 - 19 (2014)

Mechanisms of cranial placode assembly

Marie Anne Breau* and Sylvie Schneider-Maunoury

Sorbonne Universités, UPMC Univ Paris 06, UMR7622, Paris, CNRS, UMR7622, Paris and INSERM, U1156, Paris, France


Cranial placodes are transient ectodermal structures contributing to the paired sensory organs and ganglia of the vertebrate head. Placode progenitors are initially spread and intermixed within a continuous embryonic territory surrounding the anterior neural plate, the so-called pan-placodal region, which progressively breaks into distinct and compact placodal structures. The mechanisms driving the formation of these discrete placodes from the initial scattered distribution of their progenitors are poorly understood, and the implication of cell fate changes, local sorting out or massive cell movements is still a matter of debate. Here, we discuss different models that could account for placode assembly and review recent studies unraveling novel cellular and molecular aspects of this key event in the construction of the vertebrate head.


cranial placode, sensory organ, sorting-out, cell migration, coalescence

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