Smads is a new gene family in transforming growth factor-β(TGF-β) signaling pathway. Smad2 mutated in multiple human tumors and may be a candidate tumor suppressor gene. Targeted disruption of murine Smad2 gene resu...Smads is a new gene family in transforming growth factor-β(TGF-β) signaling pathway. Smad2 mutated in multiple human tumors and may be a candidate tumor suppressor gene. Targeted disruption of murine Smad2 gene resulted in embryonic lethality at E6.5. To study the function of Smad2 in vertebrate organgenesis and tumorigenesis, we constructed the Smad2 conditional targeting vector in which two LoxP sequences were placed to flank the sequences encoding the C terminal functional domain of Smad2. The validity of the LoxP sites in the targeting construct was tested in E. coli that express the Cre recombinase constitutively. The vector was electroporated into ES cells and 3 targeted ES cell clones were obtained by Southern blot screening. Targeted ES cells were introduced into C57BL/6J blastocysts by microinjection to generate germ-line chimeras. Genotyping analysis showed that 2 progeny among these chimeras carried the Smad2 conditional targeted allele. The establishment of Smad2 conditional gene targeting mouse has laid a solid foundation for producing the tissue specific Smad2 gene knockout mice.展开更多
The rat is the preferred animal model in many areas of biomedical research and drug development. Genetic manipulation in rats has lagged behind that in mice due to the lack of efficient gene targeting tools. Previousl...The rat is the preferred animal model in many areas of biomedical research and drug development. Genetic manipulation in rats has lagged behind that in mice due to the lack of efficient gene targeting tools. Previously, we generated a knockout rat via conventional homologous recombination in rat embryonic stern （ES） cells. Here, we show that efficient gene targeting in rat ES cells can be achieved quickly through transcription activator-like effector nuclease （TALEN）-mediated DNA double-strand breaks. Using the Golden Gate cloning technique, we constructed a pair of TALEN targeting vectors for the gene of interest in 5 days. After gene transfection, the targeted rat ES cell colonies were isolated, screened, and confirmed by PCR without the need of drug selection. Our results suggest that TALEN-mediated gene targeting is a superior means of establishing genetically modified rat ES cell lines with high efficiency and short turnaround time.展开更多
目的构建Cre-loxP条件性基因敲除系统中Cre酶的重组腺病毒表达载体,作为体细胞条件性基因敲除的基础,并为传统ES细胞条件性基因敲除提供新的选择。方法用pAd-easy系统在大肠杆菌内经同源重组的方法构建Cre酶的复制缺陷型重组腺病毒载体;...目的构建Cre-loxP条件性基因敲除系统中Cre酶的重组腺病毒表达载体,作为体细胞条件性基因敲除的基础,并为传统ES细胞条件性基因敲除提供新的选择。方法用pAd-easy系统在大肠杆菌内经同源重组的方法构建Cre酶的复制缺陷型重组腺病毒载体;W estern b lot方法鉴定Cre蛋白的表达。结果在大肠杆菌内构建出重组腺病毒质粒,在包装细胞系内包装出重组病毒颗粒;测定病毒滴度为106pfu/L;重组病毒在细胞内表达Cre蛋白。结论表达Cre酶的重组腺病毒载体构建成功,阳性重组质粒的鉴定方法得以改进,为进一步的体细胞Cre-loxP条件性基因敲除提供了基础。展开更多
基金This work was supported by Hi-Tech Research and Development Program of China (102-08-08-02 ) National Science Fund for Distinguished Young Scholars ( 30025028 ).
文摘Smads is a new gene family in transforming growth factor-β(TGF-β) signaling pathway. Smad2 mutated in multiple human tumors and may be a candidate tumor suppressor gene. Targeted disruption of murine Smad2 gene resulted in embryonic lethality at E6.5. To study the function of Smad2 in vertebrate organgenesis and tumorigenesis, we constructed the Smad2 conditional targeting vector in which two LoxP sequences were placed to flank the sequences encoding the C terminal functional domain of Smad2. The validity of the LoxP sites in the targeting construct was tested in E. coli that express the Cre recombinase constitutively. The vector was electroporated into ES cells and 3 targeted ES cell clones were obtained by Southern blot screening. Targeted ES cells were introduced into C57BL/6J blastocysts by microinjection to generate germ-line chimeras. Genotyping analysis showed that 2 progeny among these chimeras carried the Smad2 conditional targeted allele. The establishment of Smad2 conditional gene targeting mouse has laid a solid foundation for producing the tissue specific Smad2 gene knockout mice.
基金supported by a NIH grant to Qi-Long Ying (R01OD010926)
文摘The rat is the preferred animal model in many areas of biomedical research and drug development. Genetic manipulation in rats has lagged behind that in mice due to the lack of efficient gene targeting tools. Previously, we generated a knockout rat via conventional homologous recombination in rat embryonic stern （ES） cells. Here, we show that efficient gene targeting in rat ES cells can be achieved quickly through transcription activator-like effector nuclease （TALEN）-mediated DNA double-strand breaks. Using the Golden Gate cloning technique, we constructed a pair of TALEN targeting vectors for the gene of interest in 5 days. After gene transfection, the targeted rat ES cell colonies were isolated, screened, and confirmed by PCR without the need of drug selection. Our results suggest that TALEN-mediated gene targeting is a superior means of establishing genetically modified rat ES cell lines with high efficiency and short turnaround time.
文摘目的构建Cre-loxP条件性基因敲除系统中Cre酶的重组腺病毒表达载体,作为体细胞条件性基因敲除的基础,并为传统ES细胞条件性基因敲除提供新的选择。方法用pAd-easy系统在大肠杆菌内经同源重组的方法构建Cre酶的复制缺陷型重组腺病毒载体;W estern b lot方法鉴定Cre蛋白的表达。结果在大肠杆菌内构建出重组腺病毒质粒,在包装细胞系内包装出重组病毒颗粒;测定病毒滴度为106pfu/L;重组病毒在细胞内表达Cre蛋白。结论表达Cre酶的重组腺病毒载体构建成功,阳性重组质粒的鉴定方法得以改进,为进一步的体细胞Cre-loxP条件性基因敲除提供了基础。
