A highly sensitive yeast cell sensor constructed by overlap PCR was used to evaluate genotoxic compounds / 中国药科大学学报

@#pdr5 and snq2 gene knockout was constructed by overlap PCR, and the effects of pdr5 and snq2 mutations on the accuracy and sensitivity of RNR2 promoter-regulated yeast cell sensors in detecting genotoxic compounds were studied. The yeast cell sensors of wild-type, single-gene mutation of pdr5, single-gene mutation of snq2, and double-gene mutation of pdr5 and snq2 were studied. The cell growth inhibition and the fluorescence induction factor of the yeast cell sensors exposed to a series of concentrations of methyl methanesulfonate(MMS), ethyl methanesulfonate(EMS), cisplatin, 4-nitroquinoline-N-oxide(4NOQ), 5-fluorouracil(5-FU), hydroxyurea, salicylic acid and glucose solution were investigated. The results showed that overlap PCR method could efficiently construct the mutant yeast cell sensor. The accuracy of cell sensors of single-gene mutation of snq2 and double-gene mutation of pdr5 and snq2 were both 100%, higher than that of cell sensors of wild-type and single-gene mutation of pdr5 (87.5%). The yeast cell sensor of double-gene mutation of pdr5 and snq2 showed the highest sensitivity in detecting genotoxicity. This study provides guidance for the construction of high accuracy and sensitivity yeast cell sensor, and foundation for further functional research of yeast cell membrane transporter gene pdr5 and snq2.

Desenvolvimento de novos vetores para a produção de bibliotecas de anticorpos pelo sistema do phage display / Development of a antibody display library system targeted against vascular growth factor

Anticorpos são moléculas de grande interesse científico e farmacêutico, principalmente, devido a sua alta especificidade contra antígenos determinados. Atualmente, anticorpos monoclonais estão entre os medicamentos (biofármacos) mais vendidos do mundo. São utilizados para o tratamento das mais diversas doenças, como câncer, retinopatias, doenças inflamatórias e do sistema imune, entre outras. Nos últimos 30 anos, as tecnologias para a obtenção de anticorpos monoclonais evoluíram muito, desde a tecnologia do hibridoma, até os processos de humanização de anticorpos murinos. Entre os métodos mais utilizados para a produção de anticorpos humanos, destaca-se a tecnologia do Phage Display. Nesta técnica, os genes que codificam as regiões variáveis de imunoglobulinas são inseridos no genoma de um bacteriófago, resultando na produção de partículas virais híbridas que contém fragmentos de anticorpos em fusão com uma das proteínas do capsídeo viral. Neste trabalho, desenvolvemos novos vetores para a apresentação de fragmentos ScFv em fusão com duas proteínas das proteínas do capsídeo viral, a pIII e pVIII. Os oligonucleotídeos utilizados para amplificar os genes de imunoglobulinas foram redesenhados e para minimizar a perda do repertório durante a produção da biblioteca, avaliamos em bancos de dados enzimas de restrição que não apresentam sítios de restrição nas sequencias gênicas. Esses sítios de restrição foram utilizados para construir as regiões de clonagem do vetor Phagemid. Outra etapa crítica na produção de bibliotecas de anticorpos é a reação do PCR de overlap, que pode restringir a diversidade de anticorpos e resultar na produção de amplicons codificando anticorpos truncados. Por isso, nossos vetores foram desenhados para permitir a clonagem direta das regiões variáveis das imunoglobulinas humanas ou murinas, sem a necessidade do PCR de overlap. Nossa expectativa, é que estes novos reagentes serão mais efetivos para a produção de novas bibliotecas de anticorpos pelo sistema do Phage Display

Antibodies are molecules of great scientific and pharmaceutical interest, mainly because of their high specificity against certain antigens. Currently, monoclonal antibodies are among the best selling drugs (biopharmaceuticals) in the world. They are used for the treatment of the most diverse disorders, such as cancer, retinopathies, inflammatory and immune system diseases, among others. In the past 30 years, technologies for obtaining monoclonal antibodies has greatly evolved from hybridoma technology to the humanization processes of murine antibodies. Among the methods used for the production of human antibodies, the technology of Phage Display stands out. In this technique, the genes encoding the immunoglobulin variable regions are inserted into the genome of a bacteriophage, resulting in the production of hybrid virus particles which contain fragments of antibodies in fusion with one of the viral capsid proteins. In this work, we developed new vectors for the presentation of ScFv fragments in fusion with two proteins of viral capsid proteins, pIII and pVIII. The oligonucleotides used to amplify the immunoglobulin genes were redesigned and to minimize repertory loss during library production, we evaluated restriction enzymes in databases that lack restriction sites in the gene sequences. These restriction sites were used to construct the cloning regions of the Phagemid vector. Another critical step in the production of antibody libraries is the overlap PCR reaction, which may restrict the diversity of antibodies and result in the production of amplicons encoding truncated antibodies. Therefore, our vectors were designed to allow the direct cloning of human or murine Immunoglobulins variable regions without the need for overlap PCR. Our expectation is that these new reagents will be more effective for the production of new antibody libraries by the Phage Display system

Construction of EGFR gene G719S and T790M mutation vector and preliminary clinical application / 临床检验杂志

Objective To construct mutant recombinant vector of epidermal growth factor receptor ( EGFR) gene G719S and T790M sites associated with cervical cancer, lay the foundation for the detection of EGFR gene mutation in cervical cancer. And using it to es-tablish a molecular switch platform to detect cervical cancer EGFR gene mutations. Methods Using the wild-type recombinant plasmid as template, the mutant fusion target fragment were amplified by overlap PCR, then connect this target fragment into the vector pMD19-T. The constructed mutant recombinant plasmid was finally transformed into competent cells E.coli DH5αfurther identified by PCR with bacterial solution and genome sequencing. Establishing the molecular switch for the detection of clinical cervical cancer samples. Re-sults The G719S and T790M mutations were successfully certified by genome sequencing, and the site-directed mutant vector was successfully constructed. In addition, a molecular switch detection platform was also successfully established for the detection of cervical cancer tissue DNA. Conclusion We successfully constructed an EGFR gene mutant recombinant vector by overlap PCR technique, which providing a new technical means for gene site-directed mutagenesis. And the molecular switch detection platform was successfully established based on it, which furnishing a new method for clinical detection of EGFR gene mutations.

Construction of fused recombinant vector of EGFR gene containing G719S and T790M by overlap PCR / 临床检验杂志

Objective To construct the recombinant pMD19-exon18-exon20 plasmid containing locus G719S and T790M of EGFR gene associated with cervical cancer,which may provide a template for preparing the mutant recombinant vector of EGFR gene.Methods Using the healthy human genome DNA as templates,the segments of exon 18 and exon 20 of EGFR gene were amplified by two pairs of specific primers which were designed based on the sequences of overlapping and complementary area.The amplified segments were linked by overlap PCR.The products of linked exon18-exon20 were further inserted into the vector pMD19-T.The constructed recombi nant pMD19-exon18-exon20 plasmid was finally transformed into competent cells E.coli DH5α and then identified by PCR with bacterial solution and genome sequencing.Results The amplified fragments of exon18 and exon20 were clearly appeared at 778 bp and 596 bp and the fused product of exon18-exon20 was showed at 1 374 bp on agarose gel electrophoresis.The recombinant plasmid of fusion EGFR gene was consistent with the expected results via bacterial PCR assay and DNA sequencing.Conclusion We successfully fused the segments of exon18 with exon20 and constructed the recombinant expression vector of EGFR gene by using overlap PCR method.

A preferable approach to clone hLIF cDNA from the genomic DNA

Complementary DNA (cDNA) is valuable for investigating protein structure and function in the research of life science, but it is difficult to obtain by traditional reverse transcription. In this study, we employed a novel strategy to clone the human leukemia inhibitory factor (hLIF) gene cDNA from genomic DNA directly isolated from the mucous membrane of mouth. The hLIF sequence can be acquired within a few hours by means of amplification of each exon and splicing using overlap-PCR. Thus, the new approach developed in this study is simple, time- and cost-effective, and it is not limited to particular gene expression levels of each tissue.