Establishment of transgenic mice model with overexpression of neuritin in bone marrow / 实用医学杂志

Objective To establish transgenic mice model with over expression of neuritin in bone mar-row,for the further study on the function of neuritin protein in the treatment of peripheral neuropathy. Methods Two pairs of transgenic mice(loxp-stop-loxp-neuritin and lyz-Cre/+)were fed and propagated,the DNA from the mice tails extracted and the genotype of transgenic mice identified by PCR. The wild type mice with B6 were as-signed as the controls,and the immunofluorescence was used to detect the accuracy of the neuritinloxp/+ _lyz -Cre/+. Results The two trensgenetic homozygous mice had the ability to reproduce,and the hybrid offsprings were neuritinloxp/+_lyz-Cre/+,neuritinloxp/-_lyz-Cre/+,neuritinloxp/+_lyz-Cre/-,neuritinloxp/-_lyz-Cre/-. The re-sults were met with the Mendel′s law. The results of immunofluorescence showed that the expression of neuritin of neuritinloxp/+_lyz-Cre/+ mice in bone marrow was significantly higher than the wild type mice(P < 0.05). Con-clusion The PCR method is of high reliability for identification of sub pus genotype and the female neuritinloxp/+mice mating with the male lyz-Cre/+ ones is an effective way for obtaining the neuritinloxp/+_lyz-Cre/+ mice.

Construction and identification of conditional islet βcell DEPTOR knockout mice / 实用医学杂志

Objective To study the function of Deptor gene on the regulation of diabetes mellitus in suc-cessfully constructed and identified islet β-cell conditionally DEPTOR knockout mice model. Method By cross-breeding Deptorflox/floxmice with Cre mice expressed conditional specifically in pancreatic β-cell,Deptorflox/+Cre+/-mice were acquired and their genotypic identification was then performed. As the mice model of this study, Deptorflox/floxCre+/-mice were generated by crossing Deptorflox/+Cre+/-mice with Deptorflox/floxmice.Genotypic identifica-tion was performed by PCR at the age of 3 weeks. Tamoxifen was administered through intraperitoneal injection to induce the activation of the Cre recombination in islet beta cells of 8 weeks mice.Double immunofluorescence label-ing was then applied to identify the knockout effect of DEPTOR gene. Results Ten Islets Deptor knockout mice models were successfully acquired after 10-month cross-breeding. Validated genotype by PCR analysis were Deptorflox/floxCre+/- and double immunofluorescence labeling showed a significant difference between knockout mice and rodent controls. Conclusion Our study successfully constructs the islets conditionally Deptor deleted mice model by using Cre-loxp recombination system,providing a promising appliable animal model for study of dia-betes mellitus pathogenetic mechanism.

Construction of the markless clpP-deletion mutant of Streptococcus mutans / 中华微生物学和免疫学杂志

Objective To construct markless gene deletion mutant at the clpP loci on the chromosome of Streptococcus mutans(S.mutans).Methods ASp resistance gene was amplified by PCR,to construct the Sp resistance cassette where the Sp resistance gene was flanked with two loxP site.After the clpP gene was cloned into the pGEM-T-Easy TA cloning vector,it was digested and linked with the Sp resistance cassette,yielding homologous recombination vector pIB △ clpP-Sp.The vector was linearized and used for the transformation of S.mutans UA159,with transformants selected on TPY plates containing Sp.The selected strain was transformed with the thermosensitive plasmid pCrePA to excise the Sp resistance gene.The pCre-PA was then easily eliminated at nonpermissive temperature,resulting in a markless mutant strain carrying a deletion at the clpP loci,which was verified by PCR and DNA sequencing.Results The result of the PCR analysis and DNA sequencing indicated that a part of the clpP gene was deleted.There was a loxP at this loci without the Sp resistance gene.Conclusion The markless clpP-deletion mutant of S.mutans was constructed successfully,which laid a foundation for further study of its biological function and its influence on the cariogenicity of S.mutans.