Back to Search
Start Over
Netrin expressed by the ventral ectoderm lineage guides mesoderm migration in epibolic gastrulation of the leech.
- Source :
-
Developmental Biology . Jul2020, Vol. 463 Issue 1, p39-52. 14p. - Publication Year :
- 2020
-
Abstract
- Netrin is a remarkably conserved midline landmark, serving as a chemotactic factor that organizes the bilateral neural architecture in the post-gastrula bilaterian embryos. Netrin signal also guides cell migration in many other neural and non-neural organogenesis events in later developmental stages but has never been found to participate in gastrulation – the earliest cell migration in metazoan embryogenesis. Here, we found that the netrin signaling molecules and their receptors are expressed during gastrulation of the leech Helobdella. Intriguingly, Hau-netrin-1 was expressed in the N lineage, which gives rise in part to the ventral midline of ectoderm, at the onset of gastrulation. We demonstrated that the N lineage is required for the entrance of mesoderm into the germinal band and that misexpression of Hau-netrin-1 in early gastrulation prevented mesoderm from entering the germinal band. Together, these results suggested that Hau-netrin-1 secreted by the N lineage guides mesoderm migration during germinal band assembly. Furthermore, ectopic expression of Hau-netrin-1 after the completion of germinal band assembly disrupted the epibolic migration of the germinal bands in a later stage of gastrulation. Thus, Hau-netrin-1 is likely involved in two distinct events in sequential stages of leech gastrulation: the assembly of germinal bands in early gastrulation and their epibolic migration in mid-gastrulation. Given that the leech netrin is expressed in the precursor cells of the ventral midline during gastrulation, we propose that a heterochronic change from the midline netrin expression had taken place in the evolution of a novel mode of gastrulation in the directly developing leech embryos. Image 1 • Netrin and netrin receptors are expressed during leech gastrulation. • Leech netrins are expressed in cell lineages contributing to future midline. • Netrin guides mesoderm migration during leech gastrulation. • Netrin may contribute to the evolution of a new mode of gastrulation. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00121606
- Volume :
- 463
- Issue :
- 1
- Database :
- Academic Search Index
- Journal :
- Developmental Biology
- Publication Type :
- Academic Journal
- Accession number :
- 143417187
- Full Text :
- https://doi.org/10.1016/j.ydbio.2020.04.002