Figure 1.

Schematic representation of the segmentation clock network. Notch protein is activated by Delta ligand, and then releases NICD to induce transcription of Lfng and c-hairy-1 genes. The Lfng protein plays a negative control on the cleavage of Notch into NICD, thus forms a Notch-Lfng feedback control module. The Lfng gene can be modulated by miRNA (miR) in post-transcription level (miRNA-mediated tuner module). The c-hairy-1 protein forms a dimer to auto-regulate its own gene expression (c-hairy-1 auto-regulation module) and also inhibits the transcription of Lfng gene.