中文摘要：

肥大软骨细胞是软骨细胞的终末分化形式，在软骨内成骨过程中发挥十分关键的作用。为了研究肥大软骨细胞在骨骼发育过程中的功能，文章构建了在8．2kb小鼠X型胶原基因（Co110al）启动子控制下表达Cre重组酶的转基因小鼠品系（Co110a1（8．2）-Cre）。采用显微注射法将11．5kb的转基因片段导入小鼠基因组，共注射受精卵328枚，获得子代鼠51只，经PCR基因型鉴定有3只在基因组上整合有Cre重组酶基因。PCR检测发现Co110a1（8．2）-Cre转基因在含有肥大软骨细胞的组织中表达。为了检测Cre重组酶表达的强度和组织特异性，转基因小鼠与ROSA26报告小鼠交配，子代ROSA26；C0110a1（8．2）-Cre双转基因小鼠LacZ染色检测的结果显示，Cre重组酶在所有的肥大软骨细胞中表达。原位杂交的结果证实Co110a1（8．2）-Cre转基因表达在肥大区的上端。通过对比发现Co110a1（8．2）-Cre转基因表达的组织特异性和强度均优于之前我们构建的Co110a1（1．0）．Cre转基因品系。以上结果表明，建立的肥大软骨细胞特异性表达Cre重组酶的转基因小鼠品系可以作为一种遗传学工具，介导目的基因在肥大软骨细胞中的敲除。

英文摘要：

Hypertrophic chondrocytes, which are the terminally differentiated form of chondrocytes, play a key role in endochondral ossification. In order to investigate the functions of hypertrophic chondrocytes during bone development, we generated a new transgenic line expressing Cre recombinase under the control of a 8.2 kb mouse type X collagen gene promoter （Co110a1（8.2）-Cre）. Microinjection was employed to introduce the 11.5 kb transgenic fragment into 328 oocytes, from which 51 progenies were obtained. Three mice carrying the transgene in genome were identified by PCR genotyping. PCR detected expression of Co110a1（8.2）-Cre transgene within tissues containing hypertrophic chondrocytes. To examine the activity and specificity of Cre recombinase in vivo, transgenic line was crossed with ROSA26 report line. As indicated by LacZ staining, ROSA26; Co110a1（8.2）-Cre double transgenic mice showed efficient expression of Cre recombinase within hypertrophic chondrocytes. In situ hybridization analyses further confirmed the transcription of Co110al（8.2）-Cre transgene within the upper zone of hypertrophy, indicating a better activity and specificity in contrast to the previously constructed Co110a1（1.0）-Cre transgenic line. These results showed that this Co110a1（8.2）-Cre transgenic line could be used as a powerful tool to achieve conditional gene knockout in hypertrophic chondrocytes the activity and specificity of Cre recombinase in vivo, transgenic line was crossed with ROSA26 report line. As indicated by LacZ staining, ROSA26; CollOal（8.2）-Cre double transgenic mice showed efficient expression of Cre recombinase within hypertrophic chondrocytes. In situ hybridization analyses further confirmed the transcription of Co110a1（8.2）-Cre transgene within the upper zone of hypertrophy, indicating a better activity and specificity in contrast to the previously constructed CollOal（1.0）-Cre transgenic line. These results showed that this CollOal（8.2）-Cre transgenic line could be used as a powe