CDK1 and CDK2 regulate NICD1 turnover and the periodicity of the segmentation clock.

Francesca Anna Carrieri,Paul Davies,Philip J Murray,Jacqueline Kim Dale,Margaret Ashley Ferris,Dimitrinka Ditsova

doi:10.15252/embr.201846436

Francesca Anna Carrieri, Paul Davies + Show 4 more

Open Access

https://doi.org/10.15252/embr.201846436

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Journal: EMBO Reports	Publication Date: Apr 17, 2019
Citations: 31	License type: CC BY 4.0

Affiliation: University of Dundee, University of Washington

Abstract

All vertebrates share a segmented body axis. Segments form from the rostral end of the presomitic mesoderm (PSM) with a periodicity that is regulated by the segmentation clock. The segmentation clock is a molecular oscillator that exhibits dynamic clock gene expression across the PSM with a periodicity that matches somite formation. Notch signalling is crucial to this process. Altering Notch intracellular domain (NICD) stability affects both the clock period and somite size. However, the mechanism by which NICD stability is regulated in this context is unclear. We identified a highly conserved site crucial for NICD recognition by the SCF E3 ligase, which targets NICD for degradation. We demonstrate both CDK1 and CDK2 can phosphorylate NICD in the domain where this crucial residue lies and that NICD levels vary in a cell cycle‐dependent manner. Inhibiting CDK1 or CDK2 activity increases NICD levels both in vitro and in vivo, leading to a delay of clock gene oscillations and an increase in somite size.

Highlights

Segmentation, a process which occurs early during vertebrate body plan formation, generates repeated segments that later give rise to the vertebral column, most skeletal musculature and dermis [1,2].During somitogenesis, pairs of somites bud off the rostral end of the unsegmented presomitic mesoderm (PSM) with a periodicity that is species specific
In order to identify which kinases are involved in Notch intracellular domain (NICD) phosphorylation and which residues in the NICD PEST domain are phosphorylated rendering NICD susceptible to degradation, we employed a cellular model due to the limiting quantity of material available using embryonic cell lysates
We report for the first time that cell cycle-dependent Cyclin-dependent kinase 1 (CDK1) and Cyclin-dependent kinase 2 (CDK2) activity is involved in NICD turnover, linking NICD turnover with the cell cycle which has broad implications across all developmental and disease contexts where Notch plays a role

Summary

Introduction

Segmentation, a process which occurs early during vertebrate body plan formation, generates repeated segments (or somites) that later give rise to the vertebral column, most skeletal musculature and dermis [1,2].During somitogenesis, pairs of somites bud off the rostral end of the unsegmented presomitic mesoderm (PSM) with a periodicity that is species specific. The periodicity of segment formation is regulated by a molecular oscillator, known as the somitogenesis clock, which drives oscillatory gene expression within the PSM tissue from which somites are derived [2,3,4]. For CS, while the aetiology is unclear, linkage analyses have shown mutations in six genes (DLL3, MESP2, LFNG, HES7, TBX6 and RIPPLY2) lead to familial forms of SCD [8]. Four of these are components of the Notch pathway (DLL3, MESP2, LFNG, HES7), which plays multiple roles during segmentation. Notch is crucial to the segmentation process in mice, since in the absence of Notch signalling, the segmentation clock stops and no somites form [9]

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