Real-time imaging of the somite segmentation clock: Revelation of unstable oscillators in the individual presomitic mesoderm cells

Abstract

Expression of the bHLH gene Hes1 oscillates stably in the presomitic mesoderm (PSM) while transiently in other cells, suggesting that the Hes1 oscillators in the former and the latter could be intrinsically different. Real-time bioluminescence imaging of Hes1 expression showed that the Hes1 oscillation is robust and stable in the PSM while unstable in most individual fibroblasts and dissociated PSM cells. Thus, the Hes1 oscillators in individual PSM cells and fibroblasts are intrinsically similar, and these results, together with mathematical simulation, suggest that the cell-cell communication is essential not only for synchronization but also for stabilization of cellular oscillators.