Ripply2 recruits proteasome complex for Tbx6 degradation to define segment border during murine somitogenesis

Elife. 2018 May 15;7:e33068. doi: 10.7554/eLife.33068.

Abstract

The metameric structure in vertebrates is based on the periodic formation of somites from the anterior end of the presomitic mesoderm (PSM). The segmentation boundary is defined by the Tbx6 expression domain, whose anterior limit is determined by Tbx6 protein destabilization via Ripply2. However, the molecular mechanism of this process is poorly understood. Here, we show that Ripply2 directly binds to Tbx6 in cultured cells without changing the stability of Tbx6, indicating an unknown mechanism for Tbx6 degradation in vivo. We succeeded in reproducing in vivo events using a mouse ES induction system, in which Tbx6 degradation occurred via Ripply2. Mass spectrometry analysis of the PSM-fated ES cells revealed that proteasomes are major components of the Ripply2-binding complex, suggesting that recruitment of a protein-degradation-complex is a pivotal function of Ripply2. Finally, we identified a motif in the T-box, which is required for Tbx6 degradation independent of binding with Ripply2 in vivo.

Keywords: developmental biology; mouse; presomitic mesoderm; proteasome; segmentation; somitogenesis; stem cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cells, Cultured
  • Mass Spectrometry
  • Mice
  • Mouse Embryonic Stem Cells / physiology*
  • Proteasome Endopeptidase Complex / metabolism*
  • Protein Binding
  • Proteolysis
  • Repressor Proteins / metabolism*
  • Somites / embryology*
  • T-Box Domain Proteins
  • Transcription Factors / metabolism*

Substances

  • Repressor Proteins
  • Ripply2 protein, mouse
  • T-Box Domain Proteins
  • Tbx6 protein, mouse
  • Transcription Factors
  • Proteasome Endopeptidase Complex

Grant support

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.