OBJECTIVETo delete IL-11 receptor alpha chain gene from the Bacterial Artificial Chromosome (BAC) chimeric DNA by RecA protein mediated homologous recombination method and establish the transgenic mice model containing whole beta-globin gene cluster.

METHODSTwo 500 bp homologous sequences (A and B) located at the upstream and downstream of IL-11 receptor alpha chain gene respectively were cloned into the Hind III and Xba I sites of pBV vector, then the 1 kb A + B fragment was recovered from the building vector and inserted into the Sal I site of the shuttle vector pSV-RecA. After transforming the shuttle vector into the competent DH10B E. Coli containing BAC DNA, the IL-11 receptor alpha chain gene was finally deleted from the BAC DNA through chloramphenicol positive selection and fusaic acid negative selection. The new BAC clone was characterized by Pulse Field Gel Electrophoresis (PFGE). Then, we microinjected the linearized and purified BAC DNA into the mouse fertilized eggs and prepared the transgenic mice.

RESULTSBy RecA protein mediated homologous recombination method, we deleted the IL-11 receptor alpha chain gene from the BAC DNA containing the complete beta-globin Gene Cluster and established 3 respective transgenic mice lines.

CONCLUSIONHuman beta-globin gene cluster in the transgenic mice mediated by new BAC expresses in a correct mode and level as compared with previous transgenic mice.