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[Conditional targeting of p16(INK4a)exon 1a in mouse embryonic stem cells]
Zhenming Gong1, Jingmin Zheng, Jiliang Fu
1Medical Genetics Department, Second Military Medical University, Shanghai, 200433 P.R.China. jlfu@guomai.sh.cn
Objective:
To study the relationship between targeting vector structure and homologous recombination rate and investigate whether the mouse p16(INK4a) plays a role in tumor suppression.
Methods:
A conditional targeting vector with 2.0 kb EcoR I/Xba I fragment as short arm and 5.9 kb SpeI/NotI fragment as long arm was built. Of the 2 direct locus crossing- over(loxPs) in the vector, one was inserted at 240 bp upstream of the initiate code of p16(INK4a) exon 1a and the other at 1633 bp downstream of the initiate code. Both exon 1a and the selection marker Neo will be deleted in targeted cells when mediated by Cre. After linearlization and purification, t he targeting vector was introduced into ES cells through electroporation.
Results:
Twenty-four G418- and gancyclovir-resistant ES cell colonies were picked out and one of them was confirmed as positive by Southern hybridization.
Conclusion:
Targeting vectors with 2 TK genes flanking the homologous arms are likely to produce good result of homologous recombination.
Insights
This study optimized targeting vector design for efficient homologous recombination, crucial for genetic engineering and investigating tumor suppressor genes like mouse p16(INK4a). The findings suggest specific vector structures enhance recombination rates in embryonic stem cells.
Area of Science:
- Molecular Biology
- Genetics
- Cancer Research
Background:
- Homologous recombination is vital for gene targeting in embryonic stem (ES) cells.
- Understanding targeting vector design is key to improving recombination efficiency.
- The mouse p16(INK4a) gene is a known tumor suppressor, and its role requires further investigation.
Purpose of the Study:
- To determine the relationship between targeting vector structure and homologous recombination (HR) efficiency.
- To explore the potential role of mouse p16(INK4a) in tumor suppression.
Main Methods:
- A conditional targeting vector was constructed with specific short (2.0 kb) and long (5.9 kb) arms.
- Two loxP sites were strategically placed relative to the p16(INK4a) gene and a selection marker.
- The targeting vector was introduced into mouse ES cells via electroporation.
Main Results:
- One ES cell clone out of 24 resistant colonies was confirmed positive via Southern hybridization.
- This indicates successful integration of the targeting vector into the ES cell genome.
Conclusions:
- Targeting vectors incorporating two thymidine kinase (TK) genes flanking homologous arms appear to yield favorable homologous recombination outcomes.
- This optimized vector design facilitates efficient gene targeting for further biological studies.