Negative feedback loop formed by Lunatic fringe and Hes7 controls their oscillatory expression during somitogenesis.

Recent studies show that the cyclic expression of Lfng in the presomitic mesoderm (PSM) is controlled at the transcription level by Notch signal through the CBF1 binding site for activation and periodic repression on the Lfng promoter. Here we provide genetic evidence that the oscillatory expression is controlled by a negative feedback mechanism. We also show that Hes7, another cyclically expressed protein, can bind to the N-boxes on both Lfng and its own promoters and repress their activity. In addition, we demonstrate that the 3' untranslated region (3'-UTR) is important for rapid degradation of Lfng mRNA.