Cell dynamics during somite boundary formation revealed by time-lapse analysis.
We follow somite segmentation in living chick embryos and find that the shaping process is not a simple periodic slicing of tissue blocks but a much more carefully choreographed separation in which the somite pulls apart from the segmental plate. Cells move across the presumptive somite boundary and violate gene expression boundaries thought to correlate with the site of the somite boundary. Similarly, cells do not appear to be preassigned to a given somite as they leave the node. The results offer a detailed picture of somite shaping and provide a spatiotemporal framework for linking gene expression with cell movements.
Kulesa
Paul M
PM
Division of Biology, Beckman Institute 139-74, California Institute of Technology, Pasadena, CA 91125, USA.
Fraser
Scott E
SE
D000818:Animals; D001896:Boron Compounds; D002232:Carbocyanines; D002448:Cell Adhesion; D002465:Cell Movement; D048429:Cell Size; D002490:Central Nervous System / Q000196:embryology; D002518:Ceramides; D002642:Chick Embryo; D004847:Epithelial Cells / Q000166:cytology; D015870:Gene Expression; D020869:Gene Expression Profiling; D008648:Mesoderm / Q000166:cytology* / Q000502:physiology; D018613:Microscopy, Confocal; D008954:Models, Biological; D036122:Receptor, EphA4 / Q000235:genetics; D019170:Somites / Q000166:cytology* / Q000502:physiology*; D013997:Time Factors
C095489:4,4-difluoro-4-bora-3a,4a-diaza-s-indacene; D001896:Boron Compounds; D002232:Carbocyanines; D002518:Ceramides; C024286:3,3'-dioctadecylindocarbocyanine; D036122:Receptor, EphA4