骨形成蛋白4条件性RNA干扰小鼠的建立

Generation of bone morphogenetic protein 4 conditional RNA interference mice

为研究骨形成蛋白4(Bone morphogenetic protein 4,BMP4)在骨骼发育中的作用,我们以含有LoxPneo的pBSK/U6载体为骨架,构建小鼠BMP4条件性RNAi(conditional RNA interference),CRNA;载体(BMP4CRNAi),经KpnⅠ和AflⅢ双酶切获取针对bmp4并含neo基因的目的干扰片段,纯化后的目的片段显微注射入0.5d的FVB/NJ小鼠受精卵,并植入同期发情的假孕母鼠中,获取G0代转基因小鼠;利用PCR对G0代转基因小鼠基因型进行鉴定,PCR阳性的小鼠与FVB/NJ小鼠交配,最终获取稳定传代的BMP4CRNAi小鼠。稳定传代的BMP4CRNAi小鼠与成骨和软骨前体细胞表达Cre的转基因小鼠(Col2a1-Cre)交配,获取BMP4Col2a1-CRNAi小鼠。分离BMP4Col2a1-CRNAi小鼠原代软骨细胞,提取总RNA,利用半定量RT-PCR检测RNA干扰效率。小鼠基因型鉴定结果表明:成功获得条件性RNAi转基因小鼠;BMP4干扰效率检测结果表明:在软骨细胞中BMP4的干扰效率为81%。以上结果表明,我们成功制备了BMP4CRNAi小鼠和BMP4Col2a1-CRNAi小鼠,BMP4CRNAi小鼠与不同Cre转基因小鼠交配,可以研究BMP4在不同细胞、组织和器官的功能,BMP4Col2a1-CRNAi小鼠的获得为研究BMP4在软骨发育中的作用提供了合适的动物模型。

To explore bone morphogenetic protein 4 （BMP4） function in the developing bone, a BMP4 conditional RNA interference （CRNAi） vector was constructed based on the pBSK/U6 vector with a LoxPneo cassette. The transgene fragment targeting bmp4 was obtained by Kpn Ⅰ and AflⅢ double digestion and was purified before being microinjected into fertilized eggs from FVB/NJ mice. BMP4^CRNAi transgenic mice were genotyped by PCR. And the PCR positive mice were crossed with Col2a1-Cre transgenic mice, whose Cre recombinase was specifically expressed in osteo-chondro-progenitor cells. Bmp4 mRNA expression in primary chondrocytes were examined by semi-quantitive RT-PCR to determine RNA interference efficiency. Results showed that BMP4^CRNAi mice and BMP4^Col121-CRNAi mice were produced successfully, and bmp4 knockdown efficiency in primary chondrocytes of BMP4^Col2a1-CRNAi mice was 81%. This transgenic mouse line pro- vides excellent model for studying the role of BMP4 in chondrocyte development, and BMP4^CRNAi mouse may be a good model for studying the role of BMP4 in different cells, tissues and organs through crossing with different Cre transgenic mice.