Normal and aberrant craniofacial myogenesis by grafted trunk somitic and segmental plate mesoderm.

摘要: Our research assesses the ability of three trunk mesodermal populations– medial and lateral halves newly formed somites, presomitic (segmental plate) mesenchyme – to participate in differentiation and morphogenesis craniofacial muscles. Grafts from quail donor embryos were placed pockets adjacent midbrain-hindbrain boundary, prior onset neural crest migration, chick host embryos. This encompasses site where rectus proximal first branchial arch muscle primordia arise. The distribution of graft-derived cells were assayed using QCPN QH1 antibodies identify all quail endothelial cells, respectively. Chimeric were assayed for expression myf5, myod, paraxis lbx1 , and the synthesis myosin heavy chain (MyHC), between 1 6 days later (stages 14-30). Heterotopic control (orthotopic) transplants consistently produced invasive angioblasts, contributed first branchial arch muscles; many also dorsal oblique muscle. The spatiotemporal patterns transcription factor MyHC by these mimicked those normal head grafts also gave rise ectopic These observed somite-like condensations at implant site, dense mesenchymal aggregates to the boundary, numerous small condensations scattered deep margin eye. Cells expressed trunk factors differentiated rapidly, mimicking trunk myogenic timetable. A novel discovery was formation by grafted trunk mesoderm mononucleated myocytes irregularly oriented myotubes deep to results establish that environment is able to support progressive several distinct myogenic progenitor populations, over-riding whatever biases present time of grafting. spatial temporal differentiation and morphogenesis are very specific, mesoderm outside these sites normally refractory to, or inhibited by, signals initiate ectopic myogenesis cells.