3results about How to "Improve expression strength" patented technology

This invention discloses a high-efficiency protein expression system, its construction method, and its applications. The system includes a heterozygous promoter activator and a heterozygous promoter. The heterozygous promoter activator consists of the DNA-binding protein TetR, a linker peptide, and the transcription activator Mit1-Δ60-96. The heterozygous promoter consists of the protein-binding sequence TetO, a spacer sequence, and a basal promoter. The linker peptide is (GGGGS)×2, the spacer sequence is TCGCGCGC, and the basal promoter is P. AOX1 The core promoter of this invention. In the absence of a heterozygous promoter activator, the target protein gene initiated by the heterozygous promoter is expressed very weakly; in the presence of a heterozygous promoter activator, the target protein gene is expressed efficiently. This invention's system has good applicability and scalability, and the expression intensity of various target proteins, including xylanase, phytase, and glucosidase, is significantly higher than that of commonly used P. AOX1 Promoter.

The application discloses a cationic lipid compound, a lipid nanoparticle constructed by the cationic lipid compound, a pharmaceutical composition and purposes, the lipid nanoparticle constructed by the cationic lipid compound (formula I) has small particle size and low polymorphous index, has extremely high encapsulation efficiency on a drug molecule, can accurately deliver the mRNA drug loaded therein to the liver under the premise of keeping high expression intensity, is hardly expressed in other organs, such as lungs, hearts and kidneys, is slightly expressed in the spleen, and has important clinical application significance in cancer treatment.

The invention discloses application of myricetin in proliferation and differentiation of intestinal stem cells, and belongs to the field of organoid culture. After the organ-like model is treated by myricetin, the relative expression quantity of Lgr5 mRNA is remarkably increased, which indicates that the model can respond to intervention of myricetin, up-regulate expression of an intestinal stem cell marker Lgr5, and contribute to proliferation and tissue repair of intestinal stem cells. Immunofluorescence detection shows that the protein expression intensity of the myricetin group MUC2 is enhanced, which proves that the model can verify the promotion effect of myricetin on goblet cell differentiation and mucus secretion and improve the intestinal barrier function. QPCR detection proves that after myricetin treatment, the relative expression quantity of mRNA closely connected with related genes ZO-1, Occludin and Claudin-1 is remarkably increased, which indicates that the organ model can evaluate the protection and strengthening effects of myricetin on intestinal epithelium close connection, and has potential application value in treatment of intestinal barrier injury related diseases.