Related Experiment Video
Updated: Feb 21, 2026
Retrieval of Mouse Oocytes
Published on: April 28, 2007
Production of cloned mice using oocytes derived from ICR-outbred strain
Yoshiaki Tanabe1, Hiroki Kuwayama1, Sayaka Wakayama2
1Faculty of Life and Environmental SciencesUniversity of Yamanashi, Yamanashi, Japan.
Abstract:
Recently, it has become possible to generate cloned mice using a somatic cell nucleus derived from not only F1 strains but also inbred strains. However, to date, all cloned mice have been generated using F1 mouse oocytes as the recipient cytoplasm. Here, we attempted to generate cloned mice from oocytes derived from the ICR-outbred mouse strain. Cumulus cell nuclei derived from BDF1 and ICR mouse strains were injected into enucleated oocytes of both strains to create four groups. Subsequently, the quality and developmental potential of the cloned embryos were examined. ICR oocytes were more susceptible to damage associated with nuclear injection than BDF1 oocytes, but their activation rate and several epigenetic markers of reconstructed cloned oocytes/embryos were similar to those of BDF1 oocytes. When cloned embryos were cultured for up to 4 days, those derived from ICR oocytes demonstrated a significantly decreased rate of development to the blastocyst stage, irrespective of the nuclear donor mouse strain. However, when cloned embryos derived from ICR oocytes were transferred to female recipients at the two-cell stage, healthy cloned offspring were obtained at a success rate similar to that using BDF1 oocytes. The ICR mouse strain is very popular for biological research and less expensive to establish than most other strains. Thus, the results of this study should promote the study of nuclear reprogramming not only by reducing the cost of experiments but also by allowing us to study the effect of oocyte cytoplasm by comparing it between strains.
Insights
Researchers successfully generated cloned mice using oocytes from the common ICR strain, overcoming previous limitations with F1 strains. This breakthrough facilitates nuclear reprogramming studies and reduces experimental costs.
Area of Science:
- Reproductive biology
- Developmental biology
- Genetics
Background:
- Cloned mice generation previously relied on F1 strain oocytes.
- Inbred strains and F1 strains have been used as nuclear donors.
- ICR-outbred mouse oocytes have not been utilized for cloning.
Purpose of the Study:
- To investigate the feasibility of generating cloned mice using ICR-outbred mouse oocytes.
- To compare the developmental potential of cloned embryos derived from ICR oocytes versus BDF1 oocytes.
- To assess the impact of ICR oocytes on nuclear reprogramming and subsequent offspring development.
Main Methods:
- Somatic cell nuclear transfer was performed using cumulus cell nuclei from BDF1 and ICR mice.
- Nuclei were injected into enucleated oocytes from both BDF1 and ICR strains, creating four experimental groups.
- Cloned embryo development was assessed in vitro, and viable embryos were transferred to surrogate mothers.
Main Results:
- ICR oocytes showed increased susceptibility to nuclear injection damage but similar activation rates and epigenetic markers compared to BDF1 oocytes.
- Cloned embryos derived from ICR oocytes exhibited reduced development to the blastocyst stage in vitro.
- Despite lower in vitro development, cloned embryos from ICR oocytes resulted in healthy offspring at a success rate comparable to BDF1 oocytes after transfer.
Conclusions:
- ICR-outbred mouse oocytes can support the development of healthy cloned offspring, despite challenges in in vitro development.
- This study expands the utility of ICR oocytes for cloning, potentially lowering research costs.
- The findings enable comparative studies on the influence of oocyte cytoplasm in nuclear reprogramming across different mouse strains.
Related Concept Videos
01:08Cloning of Dolly the Sheep
01:27Reproductive Cloning
Somatic Cell Nuclear Transfer
In SCNT, an egg cell is taken from an animal and its nucleus is removed, creating an enucleated egg. Then a somatic...