[The transgenic mice specifically express Cre recombinase in central nerve system]

For specific expressing Cre recombinase in central nerve system (CNS), a transgenic construct (pGFAP-Cre-hGH), containing the beta-globin insulators, 1.8 kb of glial fibrillary acidic protein gene (GFAP) 5' end regulation region, Cre gene and polyA of human growth hormone gene (hGH) was generated, in which the 5' end regulation region of GFAP was isolated from a 129sv mouse genomic DNA library with PCR-screening. 7.6 kb of pGFAP-Cre-hGH DNA fragment was introduced into 191 fertilized eggs by microinjection. 176 injected eggs were implanted into the oviducts of eight female mice respectively, from which 25 offspring were obtained. Seven mice carry the Cre genes by the identification of PCR and Southern blotting, and the integration efficiency is 28%. The GFAP-Cre transgenic mice were crossed with ROSA26 mice whose genomic DNA is integrated by LoxP sites and LacZ expression frame to check the activity and the tissue-specific expression of Cre recombinase and recombination with its mediation between two LoxP sites. The results of LacZ dying showed that the Cre recombinase was expressed only in CNS and successfully mediated the recombination between the LoxP sites in vivo.