And the segmentation clock keeps ticking.
The vertebrate body is organized in segments, easily visible in the consecutive vertebrae of the skeleton. These are first defined in the embryo by the formation of somites. Somites are generated at regular intervals from the presomitic mesoderm by a combination of oscillating signals, known as the segmentation clock, which establish the pace at which new somites are formed, and signaling gradients that set the location of new intersomitic borders. Using a microarray approach, Dequéant et al. have now shown that the segmentation clock is more complex than previously thought and includes oscillating expression of genes from at least three signaling pathways organized in coordinated networks.
Mallo
Moisés
M
Instituto Gulbenkian de Ciência, Rua da Quinta Grande 6, 2780-156 Oeiras, Portugal. mallo@igc.gulbenkian.pt
D000818:Animals; D002454:Cell Differentiation; D018507:Gene Expression Regulation, Developmental; D019170:Somites / Q000166:cytology* / Q000378:metabolism*; D013997:Time Factors