Open AccessAn early role for Sonic hedgehog from foregut endoderm in jaw development: Ensuring neural crest cell survival
Author(s) -
José M. Brito,
Marie-Aimée Teillet,
Nicole M. Le Douarin
Publication year - 2006
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.0604751103
Subject(s) - endoderm , foregut , biology , neural crest , sonic hedgehog , anatomy , somite , embryogenesis , mesoderm , neural plate , fate mapping , forebrain , microbiology and biotechnology , embryo , embryonic stem cell , stem cell , endocrinology , central nervous system , genetics , progenitor cell , signal transduction , gene
We have investigated the role of Sonic hedgehog (Shh) in the development of facial structures by depriving chicken embryos of the most anterior sources of this morphogen, including the prechordal plate and the anterior ventral endoderm of the foregut, before the onset of neural crest cell (NCC) migration to the first branchial arch (BA1). The entire forehead, including the foregut endoderm, was removed at 5- to 10-somite stage (ss), which led to the absence of the lower jaw when the operation was performed before 7-ss. If the embryos were deprived of their forehead at 8- to 10-ss, they were later on endowed with a lower beak. In embryos that were operated on early, the NCCs migrated normally to BA1 but were subjected to massive apoptosis a few hours later. Cell death did not occur when forehead excision was performed at a later stage. In this case, onward expression ofShh in the ventral foregut endoderm extended caudally over the excision limit, and we hypothesized that absence ofShh production by the endoderm in embryos that were operated on early could be responsible for the NCC apoptosis and the failure of BA1 development. We thus provided exogenous Shh to the embryos that were operated on before 7-ss. In this case, the development of the lower jaw was rescued. Therefore, Shh derived from the ventral foregut endoderm ensures the survival of NCCs at a critical stage of BA1 development.