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Wen-Ling Zheng

Publications and source records attributed to Wen-Ling Zheng.

At least 19 recordsLinked to original sources
PubMed2006

The effects of different sample labelling methods on signal intensities of a 60-mer diagnostic microarray.

The effects of four different labelling methods on signal intensities of a 60-mer diagnostic microarray were studied. Eighty of virus-specific oligonucleotide probes for human influenza virus were prepared in an array of 15x16 spots. RNA samples from cultured human influenza virus strains were labelled with four different methods, including direct cDNA labelling (DL), universal primer labelling (UPL), direct cDNA labelling with restriction display (DL-RD), and Cy-dUTP incorporated cDNA labelling with restriction display (IL-RD) in a signal color format. The background-subtracted signal intensities from five replicate hybridization experiments of each labelling method were analyzed using one-way analysis of variance (one-way ANOVA) and linear regression techniques. The effect of sample labelling method on background-subtracted signal intensities was significant (p<0.001) and multiple comparisons showed the differences existed mainly between DL and the other three labelling methods. The sample labelling method explained about 4.3% of signal intensity. The results demonstrated that UPL and the RD-based methods are more efficient than the conventional DL method for sample labelling, an important variation factor affecting the signal intensities in diagnostic microarrays.

Analysis of Variance↗
PubMed2006

[Effect of S-bioallethrin on human lymphocyte].

OBJECTIVE: To study the effect of the S-bioallethrin on human lymphocytes by microarray technique. METHODS: The changes of normal human lymphocytes treated with S-bioallethrin were examined with light microscope, flow cytometry, electron microscope, DNA ladder and microarray techniques. RESULTS: Morphological study showed that the lymphocytes underwent apoptosis after S-bioallethrin exposure, which as further confirmed by the expression changes of 346 genes. CONCLUSION: S-bioallethrin can induce apoptosis of normal human lymphocytes and changes in their gene expression profiles.

Allethrins↗
PubMed2005

Application of restriction display PCR technique in the preparation of cDNA microarray probes.

AIM: To develop a simplified and efficient method for the preparation of hepatitis C virus (HCV) cDNA microarray probes. METHODS: With the technique of restriction display PCR (RD-PCR), restriction enzyme Sau3A I was chosen to digest the full-length HCV cDNAs. The products were classified and re-amplified by RD-PCR. We separated the differential genes by polyacrylamide gel electrophoresis and silver staining. Single bands cut out from the polyacrylamide gel were isolated. The third-round PCR was performed using the single bands as PCR template. The RD-PCR fragments were purified and cloned into the pMD18-T vector. The recombinant plasmids were extracted from positive clones, and the target gene fragments were sequenced. The cDNA microarray was prepared by spotting RD-PCR products to the surface of amino-modified glass slides using a robot. We validated the detection of microarray by hybridization and sequence analysis. RESULTS: A total of 24 different cDNA fragments ranging from 200 to 800 bp were isolated and sequenced, which were the specific gene fragments of HCV. These fragments could be further used as probes in microarray preparation. The diagnostic capability of the microarray was evaluated after the washing and scanning steps. The results of hybridization and sequence analysis showed that the specificity, sensitivity, accuracy, reproducibility, and linearity in detecting HCV RNA were satisfactory. CONCLUSION: The RD-PCR technique is of great value in obtaining a large number of size-comparable gene probes, which provides a speedy protocol in generating probes for the preparation of microarrays. Microarray prepared as such could be further optimized and applied in the clinical diagnosis of HCV.

DNA Probes↗
PubMed2005

[Detection of human papillomavirus DNA in cervical cancer tissue by PCR and direct sequencing].

OBJECTIVE: To explore an effective method for detecting human papillomavirus (HPV) DNA in cervical cancer tissue. METHODS: HPV L1 gene fragment in cervical cancer tissue was amplified by HPV-specific PCR with consensus primers, and typing of the HPV strains was performed on the basis of sequence analysis of the PCR product. RESULTS: The positivity rates of HPV DNA was 78% in the 50 cases of cervical cancer, and mixed infection with HPV16 and HPV18 strains was the most common, which accounted for 48% on the total infections. Infection with HPV58 was detected in one case. The sequencing results showed no difference in L1 sequence between the detected samples and the standard German HPV58 strain. CONCLUSION: PCR and direct sequencing approach is effective for detecting and typing of HPV DNA in cervical cancer tissue, through which rare HPV strain or mutants of known HPV strains may not escape detection.

Adenocarcinoma↗
PubMed2005

Design and preparation of Epstein-Barr virus genome-wide cDNA probes.

OBJECTIVE: To design and clone all known and predicted coding genes of Epstein-Barr virus (EBV) as the cDNA probes for preparing the microarray for EBV detection, thereby to facilitate further investigation of the pathogenetic role of EBV. METHODS: Oligo 6.0 software, BLAST program and Primer Premier 5 software were employed to design and screen the cDNA probes of the whole EBV genome, whose length ranged from 300 to 600 mer each with high specificity. These cDNA probes obtained through PCR and reverse transcriptase (RT)-PCR amplification from the genomic DNA and RNA of B95-8 cells and nasopharyngeal carcinoma (NPC) tissue were cloned into T/A clone vector, followed by identification of these probes by sequencing analysis. RESULT AND CONCLUSION: A total of 85 gene fragments (BWRF1 gene-contained 7 repeats of open reading frames) coding for proteins and 2 EBERs in EBV genome were successfully cloned, not including LF1 and LF3 genes that did not exist in EBV genome of B95-8 cells, which provides the basis for preparing microarray to explore the role of EBV genome in its related diseases.

Base Sequence↗
PubMed2005

[A new fluorescent labeling technique in microarray studies: universal primer U2 labeling].

OBJECTIVE: To develop a new method for fluorescent labeling technique, universal primer U(2) labeling (UPL), for microarray studies. METHOD: Influenza virus RNA was labeled with four labeling methods, namely UPL, random primer, restriction display incorporation labeling method and reverse transcription coupled random primer spiking labeling method (RT-PSL), respectively, and hybridized to influenza virus oligonucleotide microarray. The signals extracted from the microarrays were analyzed with SPSS 10.0 software to compare the efficiency and reproducibility of the labeling methods. RESULTS: The fluorescence intensity, signal-to-noise ratio (SNR), true positive ratio (TPR) of the probes and reproducibility of labeling with UPL were comparable with those RD-labeling method, and higher than those of RT-PSL method. UPL reduced the complexity of the procedures in comparison with the other labeling methods. CONCLUSION: UPL labeling method can be used in research and development of the microarray technique.

Fluorescent Dyes↗
PubMed2005

[Oligonucleotide microarray for human immunodeficiency virus detection].

OBJECTIVE: To develop an oligonucleotide microarray for fast detection of human immunodeficiency virus (HIV). METHODS: With complete genome sequence of HIV-1 subtype B (U26942) as the target sequence and bioinformatics software such as DNAClub, Oligo6.0, BLAST, Alignment, oligonucleotide probes of high specificity with identical length and similar melting temperature (T(m)) were designed and synthesized. Oligonucleotide microarray was prepared using Cartesian Microarrayer. Using the plasmids of HIV-1 subtype B(U26942), C(U46016), F(AF075703), G(AF061640) and restriction display technique, Cy3-labeled HIV DNA fragments were amplified and the hybridization results were scanned and analyzed with Array-Pro. RESULTS AND CONCLUSION: Twenty-two optimized oligonucleotide microarray probes were obtained and used to prepare the oligonucleotide microarray for further screening studies. The microarray prepared significantly enhanced the sensitivity, reliability and speed of DNA assay, and possesses the potential for application in clinical setting.

Base Sequence↗
PubMed2005

Growth inhibition of K562 cells by cyclin E gene-specific small interfering RNA.

OBJECTIVE: To study the inhibitory effect of small interference RNA(siRNA) of cyclin E gene on the growth of K562 cells. METHODS: siRNA targeting the 940 bp site of the cyclin E mRNA were designed and generated by PCR amplification. The PCR products containing U6 promoter and the siRNA were then transfected into K562 cells via Lipofectamine2000. The cells transfected with non-functional siRNA served as the negative control group and those only treated with serum-free RPMI1640 as the blank control group. Cell counting, reverse transcriptase (RT)-PCR and flow cytometry were employed to evaluate the effect of RNA interference. RESULTS: Compared with the negative and blank control groups, the viable cell count in the interference group was decreased by approximately 80%, the ratio of G(1)-phase cells increased by nearly 30%, and growth arrest was observed. Cyclin E mRNA expression in the cells of the interference group was significantly lowered by about 70%; as compared with that of the negative and blank control groups, whereas the latter two groups had similar expression levels. CONCLUSION: RNA interference induces obvious inhibition of cyclin E gene expression, which consequently affects the proliferation of K562 cells.

Cell Proliferation↗
PubMed2005

[Cloning of human obesity gene and its expression in E. coli].

OBJECTIVE: To clone the obesity gene of Chinese and express human leptin in E.coli. METHOD: The obesity gene was amplified from the total RNA isolated from cultured human adipocytes of Chinese by reverse transcriptional PCR, inserted into TA-vector and cloned into the expression plasmid pBV220 after sequence identification. RESULTS: DNA sequencing confirmed that the isolated obesity gene was identical to the previously reported sequence. The recombinant plasmid pBV220-OB was constructed and leptin successfully expressed in E.coli. CONCLUSION: Successful cloning and expression of human obesity gene in E.coli may facilitate further research of the mechanism of fat metabolism and adipocyte differentiation.

Adipocytes↗
PubMed2005

[Construction and preliminary identification of subtracted cDNA library of leukemia cell line K562].

OBJECTIVE: Subtractive hybridization technology is a common method to screen and clone differentially expressed genes. This study was to construct subtracted cDNA library of leukemia cell line K562, and screen for differentially expressed genes. METHODS: cDNA fragments of K562 cells (tester), prepared by restriction display (RD), were subtracted with the Sau3A I-digested cDNA fragments of normal lymphocytes (driver). The subtracted cDNA fragments were re-amplified, and cloned into pMD18-T vectors. Positive clones were selected by blue-white screening. The inserts in plasmid were amplified by polymerase chain reaction (PCR), and some of which were sequenced. RESULTS: The subtracted library contained 360 positive clones with cDNA fragments distributed mainly from 200 to 800 bp. The 50 randomly sequenced clones were derived from 42 known genes. CONCLUSION: Specific subtracted cDNA library of K562 cells was successfully constructed with reliable quality, and may be used to further screen and clone differentially expressed genes of K562 cells.

Cloning, Molecular↗
PubMed2005

[Application of oligonucleotide microarray primer extension to detection of p53 single nucleotide polymorphisms].

BACKGROUND & OBJECTIVE: Increasing evidences imply that single nucleotide polymorphisms (SNPs) are involved in etiopathology, individual therapy, and prognosis of many diseases. Rapid and accurate SNPs detection in disease genes is vitally important for genomic research. To detect p53 SNPs, the method of an arrayed primer extension based on oligonucleotide microarray was developed. METHODS: Twelve extension primers were designed in exon 3 of p53 gene. These primers were synthesized and printed onto a microarray with 7x8 spots. The fragments of p53 DNA were extracted from K562 cells by nested polymerase chain reaction (PCR), and hybridized with the microarray. After hybridization, the primer extension reactions were carried out with DNA polymerase Klenow, labeled with Cy3-dUTP or Cy5-dCTP; the product was washed and scaned, and the fragments of p53 was sequenced by ABI3730 DNA Analyzer. RESULTS: The scanning result showed that the primer extension reactions were successful, and single base labeled with Cy3 or Cy5 was extended correctly at the end of 3'primers. The results of microarray SNPs detection were consistent with the results of sequencing verification, while much less complicated. CONCLUSION: These results indicate that the arrayed primer extension techniques are useful in parallel detecting SNPs of genes of interest, which is not only sensitive and accurate but also miniaturized the assays when analyzing multiple DNA targets with minimal reagents.

DNA Primers↗
PubMed2005

[Expression of SARS spike gene in Shizomycete pombe].

The viral spike protein is the main surface antigen of the coronavirus, and it could be useful in the research of clinical diagnosis, SARS vaccine and the structure biology.According to the analysis of the main antigen of the SARS spike protein, 5 fragments of the whole spike gene were cloned, and ligated to the vector pNMT1. Through electroporation transformantion to TCP1, the recombinant S. pombe strains capable of expressing the 5 fragments were constructed. SDS-PAGE or Western blot analysis of the induced expression products demonstrated that the 5 recombinant proteins were expressed in the fission yeast respectively.

Cloning, Molecular↗
PubMed2004

Detection of hepatitis D virus by cDNA microarray method.

BACKGROUND: Viral hepatitis is considered a major public health problem in most areas of the world. In acute and chronic infections, hepatitis D virus (HDV) infection often leads to a more severe disease. This study was designed to prepare microarrays for HDV detection. METHODS: The specific primers of PCR were designed according to the conserved region of HDV. The cDNA microarrays were prepared by spotting PCR products onto the surface of glass slides by robotics. Restriction display PCR (RD-PCR) was used to label the samples. RESULTS: Sequences were aligned, and the results showed that the products of PCR amplification were the specific gene fragments of HDV. Hybridizing signals on gene chip showed the specificity and sensitivity in detecting HDV were satisfactory. CONCLUSION: Using PCR amplified products to construct gene chips for clinical diagnosis of HDV is a quick, simple and effective method.

Base Sequence↗
PubMed2004

[The strategies of gene prolong expression in mammals].

Gene therapy holds great promises to a variety of inherited diseases. However, the limitations on extended and consistent foreign gene expression has severely hampered the development of applicable gene therapy approaches. Technologies are reviewed here including transponson integration, biolistic measures that pulse the naked plasmid into living organs, or the integration of eukaryotic cis elements into introns, 3' untranslated regions, or the integration of the EBV sequences, which could assist in the prolonged gene expression of the introduced foreign genes. These strategies may significantly promote the progresses of gene therapy.

Animals↗
PubMed2003

[Analysis of gene expression patterns of leukemia K562 cells after cytochalasin B treatment].

BACKGROUND & OBJECTIVE: The advanced technique of DNA microarray makes it possible to monitor the expression of thousands of genes simultaneously in one hybridization experiment. This technique accelerates demonstration of anti-tumor drug mechanisms and discovery of new drug targets. This study was designed to investigate the differential gene expression of K562 cells after cytochalasin B treatment using cDNA microarray. METHODS: Restriction display polymerase chain reaction (RD-PCR) products of 277 human genes were spotted on a glass slide in microarray. K562 cells grew in RPMI 1640 medium with 10 microg/ml cytochalasin B. After 24 hours, the total RNA was isolated from K562 cells, and mRNA was purified. Both mRNA from the treated K562 cells and the controlled K562 cells were reversely transcribed into cDNA and labeled with two different fluorescence dyes: Cy5 or Cy3, using a method of restriction digestion and PCR labeling (RD-PCR). The probes were hybridized to the cDNA microarrays. After high-stringent washing,the cDNA microarray was scanned for the fluorescent signals and showed difference between the two cells. RESULTS: Among the 277 target genes, 18 down-regulated genes were identified after cytochalasin B treatment. CONCLUSION: There is a consistent tendency toward lower-expressed genes in partial K562 cells after cytochalasin B treatment. Most down-regulated genes were correlated with cell proliferation, signal transduction, and transcription factor.

Cytochalasin B↗
PubMed2003

Gene expression study of Saccharomyces cerevisiae with the Agilent 2100 bioanalyser.

This study explores the restriction display-polymerase chain reaction (RD-PCR) application of a new chip-based nucleic acid analysis system (Agilent 2100 bioanalyser) in a gene differential expression study. Total RNAs is extracted from Saccharomyces cerevisiae, double-stranded complementary DNA (cDNA) is synthesised by reverse transcription from the purified messenger RNA (mRNA), RD-PCR conducted to obtain the cDNA fragments and bioanalyser and agarose gel electrophoresis compared for the analysis of RD-PCR products. The bioanalyser proved to be faster and more sensitive in separating and detecting gene fragments, and was also able to compare different gene fragments quantitatively. Using this technology, comparison of several differential gene fragments is performed.

DNA↗
PubMed2003

Cloning and sequence analysis of Bacillus thuringiensis gene fragments isolated by restriction digest PCR.

OBJECTIVE: To clone and analyze Bacillus thuringiensis gene fragments isolated by restriction digest PCR (RD-PCR). METHOD: Specific primers were designed to amplify the genes of Bacillus thuringiensis israelensis (Bti), and the PCR products were classified and re-amplified by RD-PCR to obtain the fragments for subsequent purification and cloning into the pMD18-T vectors, followed by rapid identification. The recombinant plasmids were extracted from positive clones and the target gene fragments were sequenced. RESULTS: Sequence analysis showed that all the fragments amplified were Bti genes. CONCLUSION: RD-PCR is reliable in breaking down large gene fragments into confined and shorter gene fragments for preparing microarray probes.

Bacillus thuringiensis↗