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Lineage allocation and cell polarity during mouse embryogenesis.
Martin H Johnson1, Josie M L McConnell
1Department of Anatomy, Downing Street, Cambridge CB2 3DY, UK. mhj@mole.bio.cam.ac.uk
Seminars in Cell & Developmental Biology
|July 24, 2004
Summary
Mouse blastocyst development involves cell polarization at the 8-cell stage, leading to distinct trophoblast and inner cell mass lineages. Key proteins like E-cadherin and ezrin regulate this crucial early cell fate determination.
Area of Science:
- Developmental biology
- Cell biology
- Genetics
Background:
- The initial differentiation in mammalian embryos establishes distinct cell lineages.
- Mouse blastocyst formation involves the segregation of cells into outer trophoblast and inner cell mass (ICM).
Purpose of the Study:
- To investigate the molecular mechanisms underlying the first cell lineage allocation in mouse blastocysts.
- To identify key proteins involved in blastomere polarization and subsequent lineage commitment.
Main Methods:
- Analysis of blastomere polarization at the 8-cell stage.
- Investigation of protein involvement (E-cadherin, ezrin) in cell-cell contact-mediated pathways.
- Examination of transcriptional changes following lineage commitment.
Main Results:
- Cell polarization initiates at the 8-cell stage, preceding lineage allocation.
- E-cadherin and ezrin play critical roles in establishing and stabilizing cortical organization during polarization.
- Transcriptional differences emerge concurrently with or after lineage commitment.
Conclusions:
- Early blastomere polarization, regulated by cell contact and specific proteins, is fundamental for establishing trophoblast and ICM lineages.
- Lineage commitment in mouse blastocysts is a multi-step process involving post-translational regulation and subsequent transcriptional changes.