Maroto Miguel, Dale J Kim, Dequéant Mary-Lee, Petit Anne-Cécile, Pourquié Olivier
Laboratoire de Genetique et de Physiologie du Developpement, Institut de Biologie du Developpement de Marseille, CNRS-INSERM-Universite de la Mediterranee-AP de Marseille, Campus de Luminy, Marseille, France.
Int J Dev Biol. 2005;49(2-3):309-15. doi: 10.1387/ijdb.041958mm.
Segmentation of the vertebrate body axis is initiated early in development with the sequential formation of somites. Somitogenesis is temporally regulated by a molecular oscillator, the segmentation clock, which acts within presomitic mesoderm (PSM) cells to drive periodic expression of the cyclic genes. We have investigated the kinetics of the progression of cycling gene expression along the PSM. Here we show that c-hairy1 and c-hairy2 mRNA expression traverses the PSM in an entirely progressive manner and that both these genes and c-Lfng maintain a similar anterior limit of expression during each cycle. However, some differences are seen regarding both the onset of a new oscillation of these genes and the duration of their expression in the caudal PSM. We also investigated whether oscillating cyclic gene expression in the PSM is entirely cell autonomous. We find that while small PSM explants are still able to maintain their oscillation schedule, once they are dissociated, PSM cells are no longer able to maintain synchronous oscillations. The results imply that cell communication or a community effect is essential for the normal pattern of cyclic gene expression in these cells.
脊椎动物体轴的分割在发育早期随着体节的顺序形成而启动。体节发生在时间上受分子振荡器——分割时钟调控，该时钟在体节中胚层（PSM）细胞内起作用，驱动周期基因的周期性表达。我们研究了周期基因表达沿PSM进展的动力学。在此我们表明，c-hairy1和c-hairy2 mRNA表达以完全渐进的方式穿过PSM，并且在每个周期中这两个基因以及c-Lfng都维持相似的表达前界。然而，在这些基因新振荡的起始以及它们在尾部PSM中的表达持续时间方面存在一些差异。我们还研究了PSM中振荡的周期基因表达是否完全是细胞自主的。我们发现，虽然小的PSM外植体仍能维持其振荡时间表，但一旦它们解离，PSM细胞就不再能够维持同步振荡。结果表明细胞间通讯或群体效应对于这些细胞中周期基因表达的正常模式至关重要。
