Biomedical subjects

Jian-Guang Zhou

Publications and source records attributed to Jian-Guang Zhou.

9 recordsLinked to original sources

PubMed2006

[pBR322-Red mediated gene knockin, sites and expression in E. coli chromosome].

Genes lacZ, lacY and lacA in the lac opron of E. coli chromosome were respectively substituted with gene luc by using plasmid pBR322-Red, selection-counterselection system kan/sacB and various strategies of Red homologous recombination including Red mediated linearized double-stranded DNA homologous recombination and Red mediated recombineering with overlapping single stranded DNA oligonucleotides. Then, a series of new strains, CWL2, CWL4 and CWL6, were constructed and we found that they can express protein Luc efficiently. To further study the expression of exogenous genes at the site of lacZ, we have constructed a strain named CWD1 by knockin the cholera toxin B subunit(ctxb) gene at the lacZ site, then we found that CWD1 can express protein CTB efficiently and CTB was secreted out of the cell. So we assured that the sites of structure genes in the lac operon of Escherichia coli chromosome were suitable for expressing foreign genes.

Cholera Toxin↗

PubMed2005

[Gene knockout and knockin on the Escherichia coli lac operon loci using pBR322-red system].

pBR322-Red is a newly constructed recombineering plasmid, which contains a part of the pBR322 vector, a series of regulatory elements of lambda-prophage and Red recombination genes. In the beginning, we studied the best working conditions of pBR322-Red, and then modified lac operon in E. coli W3110 chromosome using the plasmid as follow: Firstly, we knockout the lacI gene using Red-mediated recombineering with overlapping single stranded DNA oligonucleotides. Secondly, we substituded the lacA and lacY genes with lacZ, a report gene, by Red-mediated linearized double strands DNA homologous recombination. Finally, we detected the expression of lacZ on these loci for the first time. The results suggested that pBR322-Red system is suitable for modifying W3110 chromosome with various recombination strategies.

Bacteriophage lambda↗

PubMed2005

[Development of a new recombineering system by gap repair].

Using lambda phage Red recombinase mediated in vivo homologous recombination system, a 6.7 kb lambda PL operon sequence including the Red encoding genes was subcloned into pBR322 by gap repair technique, and generated a pBR322-Red recombinant plasmid that can provide the Red recombination function and can be transferred into many kinds of bacteria. To confirm the recombination functions of pBR322-Red, a single-stranded 70-bases oligo was introduced into W3110 by electroporation to create a single base T-->G mutation in galK gene on the bacterial chromosome. The result demonstrated that a new lambda Red-mediated recombineering system based on pBR322-Red was successfully established.

Bacteriophage lambda↗

PubMed2005

[Effect of PC-1 gene expression on migration ability of prostate cancer cells].

BACKGROUND & OBJECTIVE: PC-1 gene is highly expressed in C4-2 cell line, an androgen-independent and aggressive prostate cancer cell line, but lowly expressed in LNCaP cell line, an androgen-dependent prostate cancer cell line. This study was to assess the contribution of PC-1 gene to migration of prostate cancer cells. METHODS: LNCaP cell line with stable expression of PC-1 gene and C4-2 cell line with antisense nucleotide-down-regulated PC-1 were established. The migration abilities of LNCaP and C4-2 cells were tested using an in vitro transwell invasion assay. RESULTS: Migration cell count of LNCaP cells with up-regulation of PC-1 gene was similar to that of control LNCaP cells(P>0.05); migration cell count was significantly lower in C4-2 cells with down-regulation of endogenous PC-1 gene than in control C4-2 cells (P<0.05). CONCLUSION: PC-1 may be involved in the invasion of prostate cancer cells.

Cell Movement↗

PubMed2005

[Construction of recombinant plasmid using Neo/E Technology].

A new neo/E counterselection technique was set up using Red recombination, which could be used in constructing recombinant plasmid. Firstly, linear targeting cassettes were amplified by PCR; secondly, two steps of homology recombination occurred in vivo: (1) The neo/E counterselection targeting cassette, consisting of a unique endonuclease recognition site and an antibiotic resistance gene, was introduced into the targeted region. (2) The neo/E cassette was replaced in the second round of recombination by another linear targeting cassettes DNA fragment carrying the targeted gene. For selecting a correct recombinant plasmid from the mixture of nonrecombinant and recombinant clones, the unique endonuclease recognition site in the nonrecombinant clones was cut by endonuclease and then transformed into the E. coli competent cells, up to 20% correct recombinants were yielded. A recombinant plasmid of pGL3-Basic PC1900T was successfully constructed in this way. Application of this technique offers a new and highly efficient way for recombinant plasmids construction.

Bacteriophage lambda↗

PubMed2004

Translation repression by an RNA polymerase elongation complex.

Bacteriophage lambda N and bacterial Nus proteins together with a unique site NUT in the leader of the early viral N gene transcript bind RNA polymerase (RNAP) and form a highly processive antitermination complex; N bound at NUT also represses N translation. In this study, we investigate whether N and NUT cause N translation repression as part of the antitermination complex by testing conditions that inhibit the formation of the N-modified transcription complex for their effect on N-mediated translation repression. We show that nus and nut mutations that in combination destabilize multiple interactions in the antitermination complex prevent N-mediated translation repression. Likewise, transcription of the nut-N region by T7 RNAP, which does not lead to the assembly of an effective antitermination complex when N is supplied, eliminates translation repression. We also demonstrate that a unique mutant beta subunit of RNAP reduces N-mediated translation repression, and that overexpression of transcription factor NusA suppresses this defect. We conclude that the N-modified RNAP transcription complex is necessary to repress N translation.

Base Sequence↗

PubMed2004

[Research on the structure of the PSA promoter and the mechanisms of its expression regulation].

Prostate-specific antigen (PSA) as a prostate cancer marker is a chymotrypsin-like serine protease which is expressed primarily by both normal prostate epithelium and the vast majority of prostate cancers. PSA expression is tightly regulated by androgen through the activation of androgen receptor. However, in the absence of androgens, PSA gene expression can become elevated. This suggests that either the AR can be activated in the absence of androgen to elevate PSA gene expression or that another transcription factor acting on the PSA promoter is stimulated. This article reviews the research on the structure of the PSA promoter and enhancer and the mechanisms of the PSA expression.

Androgens↗

PubMed2003

[Recombineering and its application].

Driven by the need of functional genomics, a homologous recombination-based, highly efficient genetic engineering system that termed "recombineering" has recently been developed. Recombineering has been defined as a genetic engineering with phage-encoded recombination function that utilizes short homologies, a convenient term to describe homologous-dependent, recombination-mediated, genetic engineering. The bacteriophage lambda Red recombination system has critical differences from standard E. coli RecA-dependent recombination pathway. The phage systems have unique advantage in that they can catalyze efficient recombination with very short regions of sequence homology (< 50 bp). Recombineering does not require construction of plasmid or phage DNA intermediates containing the appropriately pre-engineered homology segment. All that is required in vitro is the synthesis of standard oligonucleotides or construction of PCR products that provide the homology. Importantly, they function even in the absence of RecA. These approaches do not rely on the presence of suitable restriction site, and can be used to insert, delete, clone or substitute genomic DNA sequences at any desired position on a target molecule in Escherichia Coli. Recombineering also facilitates many kinds of genomic experiments difficult to be carried out. In this article, the bacteriophage lambda Red recombinase system, the progression and applications of this powerful new technique are reviewed according to the data published recently.

Bacteriophage lambda↗

PubMed2002

[A novel system for characterization of the transcription activating proteins in mammalian cells].

A system used for detecting the transcriptional activating activity of the function-unknown gene products in mammalian cells was developed. Based on the plasmid pTet-Off and the eukaryotic expressing vector pCDNA3.1B(-)/myc-his, firstly, we constructed a set of recombinant plasmids namely pZHO1 (for cloning into the foreign gene fragment and as a negative control), pZHO2 (as a positive control). The system also includes the plasmids pTRE-luc (encoding the Firefly luciferase reporter gene) and pRL-TK (encoding Renilla luciferase gene as background control). To confirm the feasibility of the system, the plasmids pZHO1, pZHO2 and pZHO3 (encoding p53 transcriptional activating domain, containing 73 amino acids in its N terminal) was contransfected into such mammalian cells as C4-2, MCF-7, COS7 respectively, each with pTRE-luc and pRL-TK plasmids, the feasibility of the system was determined by comparing the relative activity of Firefly luciferase activity ratio of and Renilla in different transfecting panels. Our research result showed that the system we constructed can be used for detecting the transcriptional activating activity of the target protein molecules in mammalian cells.

Animals↗