Discovery of genes involved in facial midline specification

The patterning of the facial midline involves early specification of neural crest cells to form skeletal tissues that support the upper jaw . In order to understand the molecular mechanisms involved we have taken advantage of a beak duplication model developed in the chicken embryo. Here we can induce the transformation of the side of the beak into a second midline that is easily identifiable by the formation of a supernumerary egg tooth. The phenotype is induced by implanting two microscopic beads, one soaked in retinoic acid and the other soaked in Noggin into the side of the head of the chicken embryo. Here we use microarrays to profile expression of maxillary mesenchyme 16h after placing the beads. A subset of genes were validated using in situ hybridization and QPCR. The aims of the study are to test the function of these genes using retroviral transgenesis, knockdown with morpholinos or expression of secreted proteins and their application to the embryo.

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Nimmagadda S, Buchtová M, Fu K, Geetha-Loganathan P, Hosseini-Farahabadi S, Trachtenberg AJ, Kuo WP, Vesela I, Richman JM