Periodic repression by the bHLH factor Hes7 is an essential mechanism for the somite segmentation clock
AUTOR(ES)
Bessho, Yasumasa
FONTE
Cold Spring Harbor Laboratory Press
RESUMO
Hes7, a bHLH gene essential for somitogenesis, displays cyclic expression of mRNA in the presomitic mesoderm (PSM). Here, we show that Hes7 protein is also expressed in a dynamic manner, which depends on proteasome-mediated degradation. Spatial comparison revealed that Hes7 and Lunatic fringe (Lfng) transcription occurs in the Hes7 protein-negative domains. Furthermore, Hes7 and Lfng transcription is constitutively up-regulated in the absence of Hes7 protein and down-regulated by stabilization of Hes7 protein. Thus, periodic repression by Hes7 protein is critical for the cyclic transcription of Hes7 and Lfng, and this negative feedback represents a molecular basis for the segmentation clock.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=196074Documentos Relacionados
- Dynamic expression and essential functions of Hes7 in somite segmentation
- The bHLH gene Hes1 is essential for expansion of early T cell precursors
- The bHLH regulator pMesogenin1 is required for maturation and segmentation of paraxial mesoderm
- The basic domain of myogenic basic helix-loop-helix (bHLH) proteins is the novel target for direct inhibition by another bHLH protein, Twist.
- A cysteine residue in helixII of the bHLH domain is essential for homodimerization of the yeast transcription factor Pho4p.