3 results about "Restriction enzyme" patented technology

The invention provides a phagemid vector construction method for constructing a phage antibody library and an antibody screening method. Phagemids are filamentous phagemids containing restriction enzyme cutting sites of bovine thrombin between coat protein PIII coding genes and target gene insertion sites. The restriction enzyme cutting sites of bovine thrombin are introduced into the phagemids, and hydrolytic cleavage of protein is carried out, so that the background in which the phagemids are non-specifically eluted is reduced. By using the phagemids of the present invention, the antibody screening efficiency is higher, and the problem of low screening efficiency in a phage display technology in the prior art is solved.

The invention discloses a method and a kit used for determining human TERT gene rs2735940 site polymorphism. The method comprises following steps: human genome DNA to be determined is provided; upstream primers and downstream primers used for amplification of sequences near human TERT gene rs2735940 site are provided, wherein the downstream primers possess mismatched base C; the human genome DNA to be determined is taken as a template, and the upstream primers and the downstream primers are used for PCR amplification so as to obtain amplification products containing CYGG or CCYGG segments, wherein Y is used for representing base C or T to be determined on human TERT gene rs2735940 site; a restriction enzyme is provided; the restriction enzyme is used for enzyme digestion of the amplification products so as to obtain corresponding enzyme-digested products; and it is determined that Y is used for representing base C or T based on the enzyme-digested products. The restriction enzyme is a restriction enzyme only used for realizing restriction digestion of one segment selected from CCGG and CTGG, or one segment selected from CCCGG and CCTGG. The method is rapid and reliable, and determination cost is reduced greatly.

The invention provides a method for building stable overexpression MGST1 gene cells and primarily studying the biological characteristics of the cells. The method comprises the following steps of (1)synthesizing human MGST1 target gene segments through PCR; (2) connecting the MGST1 target gene segments with eukaryotic plasmid pcDNA3 to form eukaryotic recombinant plasmids; converting the eukaryotic recombinant plasmids into sensory bacterial cells to be cultured; and then selecting monoclone for performing PCR amplification gel electrophoresis to screen out positive clone; (3) extracting thepositive clone screened out from the step (2); analyzing the built eukaryotic recombinant plasmids by using a restriction enzyme double digestion atlas; and performing DNA sequence analysis; and (4) transfecting SPC-A-1 human lung adenocarcinoma cells by the recombinant plasmids pcDNA3-MGST1 with the correct sequence obtained in the step (3); screening SPC-A-1 cells for stably overexpressing MGST1by using G418; and observing the biological characteristics of the cells for stably overexpressing MGST1. The result shows that through the stable overexpression of the MGST1, the cell proliferationcan be promoted; the cell apoptosis can be inhibited; and the cell clone formation capability can be enhanced.