CRISPR/Cas9 Targeted Editing of Osiris24 in Drosophlia melanogaster / 中国生物化学与分子生物学报

The gene expression of Osiris is coincident with the timing of chitin deposition. Osiris gene may be involved in the developmental regulation of insect cuticle. The objective of this study is to generate the gene-edited flies with Osiris24 by CRISPR/Cas9-mediated editing system to understand the traits of Osiris24 mutant flies and the expression pattern of Osiris24. Two sgRNA targeted sequences were designed according to the sequence of exon 1 of Osiris24 and inserted into pCFD4 vector backbone. A donor vector with Gal4 protein sequence was constructed. Above two plasmids were mixed and injected into nosCas9 fly embryos to generate GO generation. The results showed that 92.8% GO flies have Gal4 protein insert in genome. Homozygous mutants of Osiris24 were lethal at the embryonic stage or first-instar stage, and no visible phenotype was observed in heterozygous mutants. Osiris24 is expressed throughout larval and pupal stages. At the larval stage, Osiris24 is mainly expressed in the integument, foregut and hind-gut, while Osiris24 is expressed in the integument and wings at the pupal stage. These results indicated that Osiris24 plays an important role in the development of Drosophila. This study provides a research model for in-depth exploration of Osiris gene function.

Cloning and expression of the hy1 gene of Enterococcus faecium and immunologenicity of the Hy1 fusion protein / 中华传染病杂志

Objective To construct a recombinant expressing plasmid of the hy1 gene of Enterococcus faecium and to express the recombinant Hy1 protein in E.coil.To explore the immune response in mice fed orally with Hyl protein.Methods hy1 gene was amplified by polymerase chain reaction(PCR)and inserted into a prokaryotic expression vector pQE-30.The recomhinant plasmids were transfected into DH5_?to express Hy1 fusion proteins,which were purified by Ni~--column. Western blot was employed to confirm the immunogenicity of the purified protein.Mice were immu- nized by feeding with the fusion protein.The concentrations of antigen-specific antibody in the serum, mucosal fluid and faces were detected by enzyme-linked immunosorbent assay(ELISA).The role of these antibodies in the anti-infection response was evaluated after the mice were challenged with TX0016.Results hy1 gene was sequenced as 1662 bp,the fusion protein encoding polypeptides of 553 amino acid residues.The relative molecular weight was 60 000 when it was determined by sodium dodecylsulfatepo-lyacry-lamide gel electropboresis(SDS-PAGE).The dissolvable expression protein accounted for 38% of total cell protein.After processed by affinity chromatography,the purity of fusion protein was above 92%.Western blot analysis confirmed that fusion protein could be specifically recognized by the anti-TX0016 serum.The concentrations of serum IgA,serum IgG,faeces sIgA and intestmucosal fluid sIgA was 0.365?0.048,0.431?0.064,0.743?0.056 and 1.112?0.113 respectively in hy1 groups and 0.051?0.013,0.098?0.019,0.102?0.032 and 0.187?0.051 respectively in control group.The differences were statistically significant.The mice survival rate after TX0016 challenge was 70% in hyl group and 50% in control group.There was significant difference between these two groups.Conclusion The results indicate that oral immunization with hyl can induce effective mueosal immune response and produce high level sIgA.

Construction of serine protease gene mutant and study on pathogenicity of serine protease gene of Entero-coccus faecalis / 中华传染病杂志

Objective To construct the serine protease gene(sprE)mutant and to study the pathogenicity of sprE gene of Enterococcus faecalis.Methods Recombinant suicide vector pCQ001 of Enterococcus faecalis with pTX4577,was constructed.Then,created isogenic sprE-deficient mu- tant(*sprE)by allelic replacement was constructed.Moreover,the growth ability and the virulence of the mutant were compared with those of the wide type in vitro and in vivo respectively.A mouse peritonitis model and a rabbit endocarditis model were utilized in the study.Results The *sprE was selected by kanamycin and identified by polymerase chain reaction(PCR),pulsed field gel electropho- resis(PFGE)and Southern blot.The evidences showed that the sprE gene had a major role in helping bacteria to resist the elevated temperature and oxidative stress.The virulence of mutant decreased af- ter sprE gene was knocked out.Conclusions The *sprE of Enterococcus faecalis is constructed suc- cessfully,sprE gene is important in the pathogenesis of Enterococcus faecalis,which probably is a major virulence factor of Enterococcus faecali.