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Primary mesenchyme cell patterning during the early stages following ingression
Robert E Peterson1, David R McClay
1Duke University, DCMB Group, Durham, NC 27710, USA.
Developmental Biology
|February 28, 2003
Summary
Sea urchin primary mesenchyme cells (PMCs) normally stay in their quadrant of origin due to mechanical constraints. However, they migrate to form larval skeleton asymmetry starting at the gastrula stage, using oral-aboral cues.
Area of Science:
- Developmental Biology
- Cell Biology
- Marine Biology
Background:
- Sea urchin primary mesenchyme cells (PMCs) undergo epithelial-to-mesenchymal transition (EMT) and migrate to form the larval skeleton.
- Understanding PMC migration patterns is crucial for deciphering developmental processes.
Purpose of the Study:
- To track the precise movement and distribution of individual primary mesenchyme cells (PMCs) during sea urchin development.
- To investigate the factors influencing PMC localization and migration patterns.
Main Methods:
- Utilized fluorescent-marked blastomeres and blastomere recombination to trace PMC lineage.
- Employed Golgi-tethered GFP (galtase-GFP) as a stable Golgi marker to track cell positions.
- Performed ectopic transplantation of micromeres to observe altered PMC migration.
Main Results:
- Progeny of a single micromere remain clustered and generally stay within their quadrant of origin (over 94%).
- Ectopic micromere placement or removal of neighboring micromeres leads to PMCs migrating into all quadrants.
- PMC migration into adjacent quadrants, establishing larval skeleton asymmetry, begins around the mid- to late-gastrula stage, utilizing oral-aboral cues.
Conclusions:
- Normal PMC restriction to a quadrant is primarily due to mechanical constraints from neighboring PMCs.
- PMC migration involves an initial longitudinal movement followed by oral-aboral directed migration influenced by ectodermal cues starting at gastrulation.