Abstract: Objective To generate microRNA miR-302s gene targeting mice. Methods The conditional gene targeting vector were generated by molecular cloning, and then the electroporation of embryonic stem (ES) cells were carried out. The targeted ES cells were screened by positive-negative selection and identified by PCR and Southern blot, and then the correct targeted ES cells were microinjected into blastula of B6(Cg)-Tyr^c-2J/J mice. Chimerical mice were generated after transplantation of the injected blastula into the host mice, and the miR-302s-LoxP gene recombinat mice were obtained after breeding. Results Eleven miR-302s chimeric mice were obtained including four male chimeras with a higher than 50% chimeric ratio. Eleven miR-302s heterozygous gene recombinat mice were generated after outbred and inbred. Conclusion The miR-302s conditional gene targeting mice were successfully obtained. This animal model provided the foundation for further study of miR-302s in vivo.

Key words: miR-302s, Conditional gene targeting mice, Embryonic stem (ES) cell, Homologous recombination