Role of sonic hedgehog signalling in the development of the branchial arches

PAGANELLI, ALEJANDRA R.; PACHECO SILVA, GRAZIELLE; LÓPEZ, SILVIA LILIANA; CARRASCO, ANDRÉS E.

Leiwen, Alemania

Congreso; 12th International Xenopus Conference; 2008

Organizing Committee: Walter Knöchel, Christof Niehrs, Thomas Pieler, Doris Wedlich

The neural crest constitutes a multipotent cell population, which gives rise to a broad range of derivatives, including pigment cells, craniofacial skeleton, connective tissues, neurons and glia of the peripheral nervous system. In Xenopus, three major populations of migrating cranial neural crest cells originate at distinct axial levels of the mid- and hindbrain and target the mandibular (first), hyoid (second) and the third and fourth branchial arches. Sonic hedgehog overexpression leads to an enlargement of the visceral and branchial arches and to an up-regulation of Fgf-8 in ectodermal cells. Conversely, knocking down Shh signaling with a morpholino antisense oligonucleotide leads to a complete disorganization of the arches and to a down-regulation of Fgf-8. These results indicate that Shh is necessary for the correct formation and patterning of the visceral and branchial arches.