Home About us Contact
|
Home About us Contact | ||
|
|
||
Quantitative Reverse Transcription PCR (quantitative + reverse_transcription_pcr)
Selected AbstractsSingle nucleotide polymorphisms 5, upstream the coding region of the NEIL2 gene influence gene transcription levels and alter levels of genetic damageGENES, CHROMOSOMES AND CANCER, Issue 11 2008Carla J. Kinslow NEIL2 (EC 4.2.99.18), a mammalian DNA glycosylase and ortholog of the bacterial Fpg/Nei, excises oxidized DNA lesions from bubble or single-stranded structures, suggesting its involvement in transcription-coupled DNA repair. Because base excision repair (BER) proteins act collectively and in a progressive fashion, their proper balance is essential for optimal repair. Thus, inter-individual variability in transcription levels of NEIL2 may predispose to compromised DNA repair capacity and genomic instability by altering the balance of critical BER proteins. In a study of lymphocytes of 129 healthy subjects, using absolute quantitative reverse transcription PCR, we found that NEIL2 transcription varied significantly (up to 63 fold) and that this variability was influenced by certain single nucleotide polymorphisms (SNPs) located 5, of the start site. Using the mutagen sensitivity assay to characterize the biological significance of these SNPs, we observed a significant increase in mutagen-induced genetic damage associated with two SNPs in the promoter region of the NEIL2 gene. To characterize the functional significance of these SNPs, we engineered luciferase-reporter constructs of the NEIL2 promotor with mutations corresponding to these SNPs. We transfected these constructs into MRC-5 cells and evaluated their impact on NEIL2 expression levels. Our results indicate that NEIL2 expression was significantly reduced by over 50% (P < 0.01) in the presence of two SNPs, ss74800505 and rs8191518, located near the NEIL2 start site, which were in significant linkage disequilibrium (D, = 73%; P < 0.05). This first report on in vivo variability in NEIL2 expression in humans identifies SNPs in the NEIL2 promoter region that have functional effects. © 2008 Wiley-Liss, Inc. [source] Deciphering regulatory mechanisms for secondary metabolite production in the myxobacterium Sorangium cellulosum So ce56MOLECULAR MICROBIOLOGY, Issue 6 2007Shwan Rachid Summary Sorangium cellulosum strains produce approximately 50% of the biologically active secondary metabolites known from myxobacteria. These metabolites include several compounds of biotechnological importance such as the epothilones and chivosazols, which, respectively, stabilize the tubulin and actin skeletons of eukaryotic cells. S. cellulosum is characterized by its slow growth rate, and natural products are typically produced in low yield. In this study, biomagnetic bead separation of promoter-binding proteins and subsequent inactivation experiments were employed to identify the chivosazol regulator, ChiR, as a positive regulator of chivosazol biosynthesis in the genome-sequenced strain So ce56. Overexpression of chiR under the control of T7A1 promoter in a merodiploid mutant resulted in fivefold overproduction of chivosazol in a kinetic shake flask experiment, and 2.5-fold overproduction by fermentation. Using quantitative reverse transcription PCR and gel shift experiments employing heterologously expressed ChiR, we have shown that transcription of the chivosazol biosynthetic genes (chiA,chiF) is directly controlled by this protein. In addition, we have demonstrated that ChiR serves as a pleiotropic regulator in S. cellulosum, because mutant strains lack the ability to develop into regular fruiting bodies. [source] A functional polymorphism in Pre-miR-146a gene is associated with prostate cancer risk and mature miR-146a expression in vivo,THE PROSTATE, Issue 5 2010Bin Xu Abstract BACKGROUND A G,>,C polymorphism (rs2910164) which is located in the sequence of miR-146a precursor, results in a change from a G:U pair to a C:U mismatch in its stem region. To explore whether rs2910164 plays any role in prostate cancer (CaP), we analyzed the association between miR-146a polymorphism and risk of CaP and the expression of miR-146a with different genotypes in CaP tissues in southern Chinese Han population. MATERIALS AND METHODS Two hundred fifty-one CaP and 280 control subjects were included in the cancer association study, and 15 CaP tissue samples were used to test the expression of the miRNA precursors by real-time quantitative reverse transcription PCR. RESULTS We found that subjects carrying CC homozygotes had a 0.65-fold reduced risk (95% CI,=,0.43,0.99) than those carrying GG/GC genotypes (P,=,0.03), and the C allele displayed a lower prevalence of CaP compared with the G allele (OR,=,0.73, 95% CI,=,0.57,0.94, P,=,0.01). Moreover, hsa-miR-146a quantification showed that homozygous carriers of the C-variant had significantly decreased miRNA levels compared to the carriers of the GG/GC genotype. CONCLUSIONS The natural genetic variation in pre-miR-146a affects the amount of mature miR-146a, contributes to the genetic predisposition to CaP. Prostate 70: 467,472, 2010. © 2009 Wiley-Liss, Inc. [source] Immunoreactivity profile of peripheral blood mononuclear cells from patients with ragweed-induced allergic rhinitisCLINICAL & EXPERIMENTAL ALLERGY, Issue 6 2007J. Sun Summary Background Seasonal rhinitis is manifested by a series of nasal symptoms in response to exposure to seasonal allergens including ragweed pollen. Understanding its immunological mechanisms may help to better manage the disease. Objective We sought to determine comprehensively ragweed-induced cytokine and chemokine production by peripheral blood mononuclear cells from normal individuals and patients with seasonal rhinitis sensitized to ragweed pollen, and to assess its regulation by exogenous IL-10. Methods Cells were cultured in the presence or absence of a purified ragweed pollen extract with or without exogenous IL-10. Cytokines and chemokines were measured in the supernatant. Gene expression was evaluated using real-time quantitative reverse transcription PCR. Results Ragweed stimulation significantly increased the production of the Th2-associated cytokines IL-5, IL-9 and IL-13, the chemokines CCL17 and CCL22 and the regulatory cytokine IL-10 in allergic patients, whereas transforming growth factor-, (TGF-,) production was increased only in normal individuals. No difference was detected between groups in the production of the Th1 cytokine IFN-, or the Th1-affiliated chemokines CXCL10 and CXCL11. Exogenous IL-10 significantly suppressed spontaneous and induced production of both Th1- and Th2-associated cytokines and chemokines. Conclusion Our work demonstrated that locally manifested allergic rhinitis is underlined by a systemic Th2 immune response specific to allergens. The molecular pathogenesis of allergic rhinitis may be linked to a compromised allergen-specific immune regulation, e.g., reduced spontaneous and allergen-induced TGF-, production in patients compared with healthy controls. Our data also show that IL-10 inhibits both the effector and directional mechanisms of allergen-specific immune response, further supporting its potential therapeutic benefit in preventing and treating allergic diseases. [source] | ||||||||||