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Updated: Aug 1, 2026
Loss- and Gain-of-function Approach to Investigate Early Cell Fate Determinants in Preimplantation Mouse Embryos
Published on: June 6, 2016
Maternal and environmental factors in early cloned embryo development
1The Fels Institute for Cancer Research and Molecular Biology and Department of Biochemistry, Temple University School of Medicine, Philadelphia, PA 19140, USA.
Abstract:
Cloning by somatic cell nuclear transfer (SCNT) in mammals has revealed the remarkable ability of an oocyte to reprogram somatic cell nuclei and induce them to recapitulate the developmental program. Despite the success, cloning remains very inefficient. This review summarizes recent observations from cloning in mice that reveal some of the likely causes for the present inefficiency. One cause appears to be the slow pace of reprogramming combined with the early onset of genome transcription, which together cause cloned embryos to elaborate many somatic cell characteristics even before the first cleavage division. The altered phenotypes of cloned embryos render standard embryo culture conditions grossly sub-optimum. Another cause appears to be a hitherto unappreciated contribution of spindle-associated factors to early embryo development. As current procedures remove the spindle and associated factors, cloned embryos lack these factors. These observations are providing new insight into basic mammalian embryology. They also reveal possible changes to protocols that could improve the overall success of cloning.
Insights
Somatic cell nuclear transfer (SCNT) cloning in mice is inefficient due to slow reprogramming and lack of spindle factors. Improving protocols could enhance cloning success rates in mammals.
Area of Science:
- Mammalian embryology
- Reproductive biology
- Developmental biology
Background:
- Somatic cell nuclear transfer (SCNT) demonstrates oocyte reprogramming potential in mammals.
- Despite SCNT's success, mammalian cloning remains highly inefficient.
Purpose of the Study:
- To review recent findings from mouse cloning that identify causes of inefficiency.
- To provide insights into mammalian embryology and suggest protocol improvements for cloning.
Main Methods:
- Review of recent observations from mouse cloning experiments.
- Analysis of factors affecting early embryonic development in cloned embryos.
Main Results:
- Slow reprogramming and early genome transcription in cloned embryos lead to persistent somatic cell characteristics before first cleavage.
- Altered phenotypes of cloned embryos make standard culture conditions suboptimal.
- Absence of crucial spindle-associated factors, removed during SCNT procedures, impacts early development.
Conclusions:
- Inefficiency in mammalian cloning stems from delayed reprogramming and loss of essential spindle factors.
- Understanding these factors offers potential strategies to improve cloning protocols and success rates.
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