Neuromesodermal progenitors are a conserved source of spinal cord with divergent growth dynamics

Abstract

During gastrulation, embryonic cells become specified into distinct germ layers. In mouse, this continues throughout somitogenesis from a population of bipotent stem cells called neuromesodermal progenitors (NMps). However, the degree of self-renewal associated with NMps in the fast-developing zebrafish embryo is unclear. Using a genetic clone-tracing method, we labelled early embryonic progenitors and found a strong clonal similarity between spinal cord and mesoderm tissues. We followed individual cell lineages using light-sheet imaging, revealing a common neuromesodermal lineage contribution to a subset of spinal cord tissue across the anterior-posterior body axis. An initial population subdivides at mid-gastrula stages and is directly allocated to neural and mesodermal compartments during gastrulation. A second population in the tailbud undergoes delayed allocation to contribute to the neural and mesodermal compartment only at late somitogenesis. Cell tracking and retrospective cell fate assignment at late somitogenesis stages reveal these cells to be a collection of mono-fated progenitors. Our results suggest that NMps are a conserved population of bipotential progenitors, the lineage of which varies in a species-specific manner due to vastly different rates of differentiation and growth.

Dynamics of primitive streak regression controls the fate of neuro-mesodermal progenitors in the chicken embryo

“…These observations are consistent with recent grafts of the epiblast territory in 6-somite chicken embryos showing that the territory first produces neural and then both mesodermal and neural derivatives (Kawachi et al, 2020). Bipotential cells with a neural and mesodermal fate have so far only been reported in zebrafish where they segregate during gastrulation and contribute to the most posterior part of the axis (Attardi et al, 2018). In zebrafish however, only monopotent cells were found in the tail bud (Attardi et al, 2018;Kanki and Ho, 1997), while that this is not the case in chicken (this report) and mouse (Tzouanacou et al, 2009).…”

“…Bipotential cells with a neural and mesodermal fate have so far only been reported in zebrafish where they segregate during gastrulation and contribute to the most posterior part of the axis (Attardi et al, 2018). In zebrafish however, only monopotent cells were found in the tail bud (Attardi et al, 2018;Kanki and Ho, 1997), while that this is not the case in chicken (this report) and mouse (Tzouanacou et al, 2009).…”

Neuromesodermal progenitors separate the axial stem zones while producing few single- and dual-fated descendants

“…Previously, two committed stem zones (mesodermal, MSZ, and neural, NSZ) were shown to drive axial elongation after gastrulation; however, indirect evidence also indicated that they share some common, neuromesodermal progenitors (NMPs) during elongation (see Introduction). These could not be directly observed and mapped in mouse (McDole et al, 2018), chick or zebrafish (Attardi et al, 2018) at elongation stages. There is also some controversy regarding their molecular definition and the interpretation of genetic manipulations at population level to deduce the individual cell behaviours fate decisions that allocate cells to the specialised stem zones (Mugele et al, 2018).…”

Regulating Retinoic Acid Availability during Development and Regeneration: The Role of the CYP26 Enzymes

“…It has been shown that these tissues are generated in a progressively more posterior fashion by proliferation and subsequent differentiation of neuromesodermal progenitors (NMPs) found at the caudal end of the embryo. To ensure the embryo reaches the correct length, careful regulation of number of progenitors induced, rate of self-maintenance/renewal and differentiation towards neural or mesodermal fates is necessary [299][300][301][302][303].…”