Multi-scalar mechanisms timing axial progenitor contribution to the vertebrate body axis
type: CreativeWork
description: Timing is a fundamental feature of embryogenesis: the embryos of a given species develop with reproducible timing and a precise ordering of events. The underlying mechanisms that control the absolute timing of cell state changes and morphogenetic events in development are largely not understood, and crucially can be considered at a wide range of length scales, from the integration of positional cues over time in a single cell to whole-organism events such as hormone release. A key context in which cell behaviour must be coordinated with time occurs in the development of the vertebrate posterior body, which is elaborated in a strict anterior to posterior sequence. This process occurs over a period of hours to days depending upon the species, necessitating mechanisms to ensure that cells are allocated to the body axis in a controlled manner. The prevailing model for regulation of the timing of progenitor contribution to the body axis centres around a changing Hox gene expression complement in the population (‘The Hox Clock’) that can influence the timing with which cells enter the body axis (Deschamps and Duboule, 2017; Iimura and Pourquie, 2006). In this thesis, I utilise classical experimental embryology approaches including grafting and explant culture in combination with modern techniques such as single cell transcriptomics and multiplexed in situ hybridisation to ask about the contribution of intrinsic and extrinsic influences to cell decisions during gastrulation and axis elongation. My primary experimental assay involves the heterochronic grafting of HH8 somite progenitors to a HH4 embryo. I show that HH8 somite progenitors undergo ingression through the primitive streak but are delayed relative to HH4 progenitors at the transition from ingressed to migratory mesenchyme, ultimately resulting in a more posterior axis contribution. To assess the role of Hox gene expression, I identified a set of genes with differential expression between HH4 and HH8 progenitor re…
abstract: Timing is a fundamental feature of embryogenesis: the embryos of a given species develop with reproducible timing and a precise ordering of events. The underlying mechanisms that control the absolute timing of cell state changes and morphogenetic events in development are largely not understood, and crucially can be considered at a wide range of length scales, from the integration of positional cues over time in a single cell to whole-organism events such as hormone release. A key context in which cell behaviour must be coordinated with time occurs in the development of the vertebrate posterior body, which is elaborated in a strict anterior to posterior sequence. This process occurs over a period of hours to days depending upon the species, necessitating mechanisms to ensure that cells are allocated to the body axis in a controlled manner. The prevailing model for regulation of the timing of progenitor contribution to the body axis centres around a changing Hox gene expression complement in the population (‘The Hox Clock’) that can influence the timing with which cells enter the body axis (Deschamps and Duboule, 2017; Iimura and Pourquie, 2006). In this thesis, I utilise classical experimental embryology approaches including grafting and explant culture in combination with modern techniques such as single cell transcriptomics and multiplexed in situ hybridisation to ask about the contribution of intrinsic and extrinsic influences to cell decisions during gastrulation and axis elongation. My primary experimental assay involves the heterochronic grafting of HH8 somite progenitors to a HH4 embryo. I show that HH8 somite progenitors undergo ingression through the primitive streak but are delayed relative to HH4 progenitors at the transition from ingressed to migratory mesenchyme, ultimately resulting in a more posterior axis contribution. To assess the role of Hox gene expression, I identified a set of genes with differential expression between HH4 and HH8 progenitor re…
author: Busby, Lara
language: eng
keywords: avian, axial progenitor, developmental biology, embryology, gastrulation, gene expression, Hox, intrinsic, mesoderm, transcriptomics
license: https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/4bb57645-d632-4adf-a8e8-dc1cfc719c2d/download
license: https://www.rioxx.net/licenses/all-rights-reserved/
date published: 2023-02-28
date modified: 2026-07-22T22:24:24Z
provider: Cambridge University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Cambridge

PropertyValue
property ID: DOI
value: 10.17863/CAM.96858