Somite boundary determination in normal and clock‐less vertebrate embryos. (28th February 2020)

• Record Type: Journal Article
• Authors: Naoki, Honda; Matsui, Takaaki
• Other Names: Morishita Y. guestEditor.; Kitajima T. guestEditor.; Tagami S. guestEditor.; Takasato M. guestEditor.; Tanaka Y. guestEditor.
• Is Part Of: Development growth and differentiation. Volume 62:Number 3(2020)
• Page Start: 177
• Page End: 187
• Publication Date: 2020-02-28
• Subjects: computational model -- developmental noise -- ERK -- live imaging -- somitogenesis; Embryology -- Periodicals; Developmental biology -- Periodicals; Growth -- Periodicals; 574.3
• DOI: 10.1111/dgd.12655
• Languages: English
• ISSNs: 0012-1592

Abstract

Abstract: Vertebrate segments called somites are generated by periodic segmentation of the presomitic mesoderm (PSM). In the most accepted theoretical model for somite segmentation, the clock and wavefront (CW) model, a clock that ticks to determine particular timings and a wavefront that moves posteriorly are presented in the PSM, and somite positions are determined when the clock meets the posteriorly moving wavefront somewhere in the PSM. Over the last two decades, it has been revealed that the molecular mechanism of the clock and wavefront in vertebrates is based on clock genes including Hes family transcription factors and Notch effectors that oscillate within the PSM to determine particular timings and fibroblast growth factor (FGF) gradients, acting as the posteriorly moving wavefront to determine the position of somite segmentation. A clock‐less condition in the CW model was predicted to form no somites; however, irregularly sized somites were still formed in mice and zebrafish, suggesting that this was one of the limitations of the CW model. Recently, we performed interdisciplinary research of experimental and theoretical biological studies and revealed the mechanisms of somite boundary determination in normal and clock‐less conditions by characterization of the FGF/extracellular signal‐regulated kinase (ERK) activity dynamics. Since features of the molecular clock have already been described in‐depth in several reviews, we summarized recent findings regarding the role of FGF/ERK signaling in somite boundary formation and described our current understanding of how FGF/ERK signaling contributes to somitogenesis in normal and clock‐less conditions in this review. Abstract : This review summarizes recent findings in the roles of FGF/ERK signaling in somite boundary formation and describes our current understanding of how FGF/ERK signaling contributes to somitogenesis in normal and clock‐less conditions.