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Updated: Mar 30, 2026
Structure-function Studies in Mouse Embryonic Stem Cells Using Recombinase-mediated Cassette Exchange
Published on: April 27, 2017
Selection and dynamics of embryonic stem cell integration into early mouse embryos
Stoyana Alexandrova1, Tuzer Kalkan2, Peter Humphreys2
1Wellcome Trust-Medical Research Council Cambridge Stem Cell Institute, University of Cambridge, Tennis Court Road, Cambridge CB2 1QR, UK Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 4BG, UK.
Embryonic stem cells (ESCs) differentiating outside the embryo are eliminated by apoptosis. This selection process ensures only undifferentiated ESCs integrate, but the embryo can redirect some primed cells to enhance development.
Area of Science:
- Developmental Biology
- Stem Cell Biology
- Cell Fate Decisions
Background:
- Embryonic stem cell (ESC) integration into host embryos is crucial for studying cell potency and fate.
- Previous research indicates limited ESC contribution to chimeric adults, with mechanisms of integration or elimination unclear.
Purpose of the Study:
- To investigate the role of cellular heterogeneity in ESC integration and elimination.
- To compare the developmental fate of heterogeneous (serum/LIF) versus homogeneous (2i/LIF) ESC cultures upon embryo incorporation.
Main Methods:
- Utilized time-lapse ex vivo imaging to observe ESC behavior post-incorporation.
- Employed a fluorescent reporter (Rex1-GFP) to track naive pluripotency.
- Compared ESCs cultured in serum/LIF (heterogeneous) with those in 2i/LIF (homogeneous).
Main Results:
- Serum/LIF ESCs showed drastic elimination during early development compared to 2i/LIF ESCs.
- Eliminated serum/LIF ESCs were identified as differentiating cells undergoing apoptosis.
- Occasional Rex1-negative cells integrated, with some upregulating Rex1 in response to the embryonic environment.
Conclusions:
- A selection process actively eliminates differentiating ESCs from the host embryo via apoptosis.
- The embryonic environment can influence cell fate, promoting dedifferentiation or enhancing pluripotency in integrated cells.
