Generation of RNase L knockout cell lines by CRISPR/Cas system / 军事医学

Objective To establish RNase L gene knockout HEK 293 cell lines using CRISPR/Cas9 system.Methods Small guide RNA ( sgRNA) sequences of human RNase L were designed and sgRNAs were inserted into pCas-Guide and pCas-guide RNA(gRNA) vectors were obtained.The donor DNA sequences of the homologous arm were designed for RNase L knockout .In the presence of the right homologous arm , the resistance gene of hygromycin B and the left homologous arm as templates of homology-directed repair , the donor DNA template was amplified by overlopping PCR and cloned into the pBackZero-T expression vector and pBackZero-T-RNase LK vector was obtained .The pCas-gRNA vector and pBackZero-T-RNase LK vector were co-transfected into HEK293 cells to establish the stable expression cell line of RNase L gene knockout .Cells were cultured with hygromycin B , while Western blotting and DNA sequencing were used to analyze the gene of RNase L knockout from genome .Results and Conclusion The pCas-gRNA vector and pBackZero-T-RNase LK vector were successfully constructed.Five RNase L gene knockout HEK293 cell lines were generated,contributing to the study of the biological function and molecular mechanism of RNase L .

Highly Efficient Electroporation-mediated Transformation into Edible Mushroom Flammulina velutipes

In this study, we developed an efficient electroporation-mediated transformation system featuring Flammulina velutipes. The flammutoxin (ftx) gene of F. velutipes was isolated by reverse transcription-PCR. pFTXHg plasmid was constructed using the partial ftx gene (410 bp) along with the hygromycin B phosphotransferase gene (hygB) downstream of the glyceraldehydes-3-phosphate dehydrogenase (gpd) promoter. The plasmid was transformed into protoplasts of monokaryotic strain 4019-20 of F. velutipes by electroporation. High transformation efficiency was obtained with an electric-pulse of 1.25 kV/cm by using 177 transformants/microg of DNA in 1 x 107 protoplasts. PCR and Southern blot hybridization indicated that a single copy of the plasmid DNA was inserted at different locations in the F. velutipes genome by non-homologous recombination. Therefore, this transformation system could be used as a useful tool for gene function analysis of F. velutipes.

Integration and Expression of BGL1 Gene from Saccharomy-copsis fibuligera in Industrial Saccharomyces cerevisiae / 微生物学通报

The recombinant plasmid pPIC-gpd-bgl-hyg was constructed, which contained GPD2 promotor and terminator from industrial yeasts Saccharomyces cerevisiae, ?-glucosidase gene (BGL1) from Sac-charomycopsis fibuligera and hyg from hygromycin as the selected marker. With the yeast’s high efficiency of homologous integrated, the BGL1 gene was successfully integrated into industrial yeasts S. cerevisiae. The recombined yeast could grow on the cultures with the cellobiose as a sole carbon source, and the ?-glucosidase activity achieved 0.764 U/mL after 48 hours’ cultivation. In the experiments of VHG ethanol fermentation, the cellobiose concentration in broth of recombined yeast was 80% lower than that of indus-trial yeast.