Polymerase III (polymerase + iii)

Distribution by Scientific Domains

Kinds of Polymerase III

  • rna polymerase iii


  • Selected Abstracts


    Close temporal relationship between onset of cancer and scleroderma in patients with RNA polymerase I/III antibodies

    ARTHRITIS & RHEUMATISM, Issue 9 2010
    Ami A. Shah
    Objective This study was undertaken to examine the temporal relationship between scleroderma development and malignancy, and to evaluate whether this differs by autoantibody status among affected patients. Methods Study participants had a diagnosis of scleroderma, a diagnosis of cancer, cancer, an available serum sample, and a cancer pathology specimen. Sera were tested for autoantibodies against topoisomerase I, centromere, and RNA polymerase I/III by immunoprecipitation and/or enzyme-linked immunosorbent assay. Clinical and demographic characteristics were compared across autoantibody categories. Expression of RNA polymerases I and III was evaluated by immunohistochemistry using cancerous tissue from patients with anti,RNA polymerase antibodies. Results Twenty-three patients were enrolled. Six patients tested positive for anti,RNA polymerase I/III, 5 for anti,topoisomerase I, and 8 for anticentromere, and 4 were not positive for any of these antigens. The median duration of scleroderma at cancer diagnosis differed significantly between groups (,1.2 years in the anti,RNA polymerase I/III group, +13.4 years in the anti,topoisomerase I group, +11.1 years in the anticentromere group, and +2.3 years in the group that was negative for all antigens tested) (P = 0.027). RNA polymerase III demonstrated a robust nucleolar staining pattern in 4 of 5 available tumors from patients with antibodies to RNA polymerase I/III. In contrast, nucleolar RNA polymerase III staining was not detected in any of 4 examined tumors from the RNA polymerase antibody,negative group (P = 0.048). Conclusion Our findings indicate that there is a close temporal relationship between the onset of cancer and scleroderma in patients with antibodies to RNA polymerase I/III, which is distinct from scleroderma patients with other autoantibody specificities. In this study, autoantibody response and tumor antigen expression are associated. We propose that malignancy may initiate the scleroderma-specific immune response and drive disease in a subset of scleroderma patients. [source]


    Effect of deletion of SOS-induced polymerases, pol II, IV, and V, on spontaneous mutagenesis in Escherichia coli mutD5

    ENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 4 2004
    Anetta Nowosielska
    Abstract The E. coli dnaQ gene encodes the , subunit of DNA polymerase III (pol III) responsible for the proofreading activity of this polymerase. The mutD5 mutant of dnaQ chronically expresses the SOS response and exhibits a mutator phenotype. In this study we have constructed a set of E. coli AB1157 mutD5 derivatives deleted in genes encoding SOS-induced DNA polymerases, pol II, pol IV, and pol V, and estimated the frequency and specificity of spontaneous argE3,Arg+ reversion in exponentially growing and stationary-phase cells of these strains. We found that pol II exerts a profound effect on the specificity of spontaneous mutation in exponentially growing cells. Analysis of growth-dependent Arg+ revertants in mutD5 polB+ strains revealed that Arg+ revertants were due to tRNA suppressor formation, whereas those in mutD5 ,polB strains arose by back mutation at the argE3 ochre site. In stationary-phase bacteria, Arg+revertants arose mainly by back mutation, regardless of whether they were proficient or deficient in pol II. Our results also indicate that in a mutD5 background, the absence of pol II led to increased frequency of Arg+ growth-dependent revertants, whereas the lack of pol V caused its dramatic decrease, especially in mutD5 ,umuDC and mutD5 ,umuDC ,polB strains. In contrast, the rate of stationary-phase Arg+revertants increased in the absence of pol IV in the mutD5 ,dinB strain. We postulate that the proofreading activity of pol II excises DNA lesions in exponentially growing cells, whereas pol V and pol IV are more active in stationary-phase cultures. Environ. Mol. Mutagen. 43:226,234, 2004. © 2004 Wiley-Liss, Inc. [source]


    Rpc25, a conserved RNA polymerase III subunit, is critical for transcription initiation

    MOLECULAR MICROBIOLOGY, Issue 1 2005
    Cécile Zaros
    Summary Rpc25 is a strongly conserved subunit of RNA polymerase III with homology to Rpa43 in RNA polymerase I, Rpb7 in RNA polymerase II and the archaeal RpoE subunit. A central domain of Rpc25 can replaced the corresponding region of Rpb7 with little or no growth defect, underscoring the functional relatedness of these proteins. Rpc25 forms a heterodimer with Rpc17, another conserved component of RNA polymerase III. A conditional mutant (rpc25-S100P) impairs this interaction. rpc25-S100P and another conditional mutant obtained by complementation with the Schizosaccharomyces pombe subunit (rpc25-Sp) were investigated for the properties of their purified RNA polymerase III. The mutant enzymes were defective in the specific synthesis of pre-tRNA transcripts but acted at a wild-type level on poly[d(A-T)] templates. They were also indistinguishable from wild type in transcript elongation, cleavage and termination. These data indicate that Rpc25 is needed for transcription initiation but is not critical for the elongating properties of RNA polymerase III. [source]


    Widespread distribution of a lexA -regulated DNA damage-inducible multiple gene cassette in the Proteobacteria phylum

    MOLECULAR MICROBIOLOGY, Issue 1 2004
    Marc Abella
    Summary The SOS response comprises a set of cellular functions aimed at preserving bacterial cell viability in front of DNA injuries. The SOS network, negatively regulated by the LexA protein, is found in many bacterial species that have not suffered major reductions in their gene contents, but presents distinctly divergent LexA-binding sites across the Bacteria domain. In this article, we report the identification and characterization of an imported multiple gene cassette in the Gamma Proteobacterium Pseudomonas putida that encodes a LexA protein, an inhibitor of cell division (SulA), an error-prone polymerase (DinP) and the alpha subunit of DNA polymerase III (DnaE). We also demonstrate that these genes constitute a DNA damage-inducible operon that is regulated by its own encoded LexA protein, and we establish that the latter is a direct derivative of the Gram-positive LexA protein. In addition, in silico analyses reveal that this multiple gene cassette is also present in many Proteobacteria families, and that both its gene content and LexA-binding sequence have evolved over time, ultimately giving rise to the lexA lineage of extant Gamma Proteobacteria. [source]


    Sequence-specific inhibition of RNA polymerase III-dependent transcription using Zorro locked nucleic acid (LNA)

    THE JOURNAL OF GENE MEDICINE, Issue 1 2008
    Rongbin Ge
    Abstract Background RNA polymerase III (pol III)-dependent transcripts are involved in many fundamental activities in a cell, such as splicing and protein synthesis. They also regulate cell growth and influence tumor formation. During recent years vector-based systems for expression of short hairpin (sh) RNA under the control of a pol III promoter have been developed as gene-based medicines. Therefore, there is an increasing interest in means to regulate pol III-dependent transcription. Recently, we have developed a novel anti-gene molecule ,Zorro LNA (Locked Nucleic Acid)', which simultaneously hybridizes to both strands of super-coiled DNA and potently inhibits RNA polymerase II-derived transcription. We have now applied Zorro LNA in an attempt to also control U6 promoter-driven expression of shRNA. Methods In this study, we constructed pshluc and pshluc2BS plasmids, in which U6 promoter-driven small hairpin RNA specific for luciferase gene (shluc) was without or with Zorro LNA binding sites, respectively. After hybridization of Zorro LNA to pshluc2BS, the LNA-bound plasmid was cotransfected with pEGFPluc into mammalian cells and into a mouse model. In cellular experiments, cotransfection of unhybridized pshluc2BS, Zorro LNA and pEGFPluc was also performed. Results The results showed that the Zorro LNA construct efficiently inhibited pol III-dependent transcription as an anti-gene reagent in a cellular context, including in vivo in a mouse model. Conclusions Thus, this new form of gene silencer ,Zorro LNA' could potentially serve as a versatile regulator of pol III-dependent transcription, including various forms of shRNAs. Copyright © 2007 John Wiley & Sons, Ltd. [source]


    Comparison of bovine RNA polymerase III promoters for short hairpin RNA expression

    ANIMAL GENETICS, Issue 4 2006
    L. S. Lambeth
    Summary RNA interference (RNAi) mediated by DNA-based expression of short hairpin RNA (shRNA) is a powerful method of sequence-specific gene knockdown. A number of vectors for expression of shRNA have been developed that feature promoters from RNA polymerase III (pol III)-transcribed genes of mouse or human origin. To advance the use of RNAi as a tool for functional genomic research and for future development of specific therapeutics in the bovine species, we have developed shRNA expression vectors that feature novel bovine RNA pol III promoters. We characterized two bovine U6 small nuclear RNA (snRNA) promoters (bU6-2 and bU6-3) and a bovine 7SK snRNA promoter (b7SK). We compared the efficiency of each of these promoters to express shRNA molecules. Promoter activity was measured in the context of RNAi by targeting and suppressing the reporter gene encoding enhanced green fluorescent protein. Results show that the b7SK promoter induced the greatest level of suppression in a range of cell lines. The comparison of these bovine promoters in shRNA expression is an important component for the future development of bovine-specific RNAi-based research. [source]


    Close temporal relationship between onset of cancer and scleroderma in patients with RNA polymerase I/III antibodies

    ARTHRITIS & RHEUMATISM, Issue 9 2010
    Ami A. Shah
    Objective This study was undertaken to examine the temporal relationship between scleroderma development and malignancy, and to evaluate whether this differs by autoantibody status among affected patients. Methods Study participants had a diagnosis of scleroderma, a diagnosis of cancer, cancer, an available serum sample, and a cancer pathology specimen. Sera were tested for autoantibodies against topoisomerase I, centromere, and RNA polymerase I/III by immunoprecipitation and/or enzyme-linked immunosorbent assay. Clinical and demographic characteristics were compared across autoantibody categories. Expression of RNA polymerases I and III was evaluated by immunohistochemistry using cancerous tissue from patients with anti,RNA polymerase antibodies. Results Twenty-three patients were enrolled. Six patients tested positive for anti,RNA polymerase I/III, 5 for anti,topoisomerase I, and 8 for anticentromere, and 4 were not positive for any of these antigens. The median duration of scleroderma at cancer diagnosis differed significantly between groups (,1.2 years in the anti,RNA polymerase I/III group, +13.4 years in the anti,topoisomerase I group, +11.1 years in the anticentromere group, and +2.3 years in the group that was negative for all antigens tested) (P = 0.027). RNA polymerase III demonstrated a robust nucleolar staining pattern in 4 of 5 available tumors from patients with antibodies to RNA polymerase I/III. In contrast, nucleolar RNA polymerase III staining was not detected in any of 4 examined tumors from the RNA polymerase antibody,negative group (P = 0.048). Conclusion Our findings indicate that there is a close temporal relationship between the onset of cancer and scleroderma in patients with antibodies to RNA polymerase I/III, which is distinct from scleroderma patients with other autoantibody specificities. In this study, autoantibody response and tumor antigen expression are associated. We propose that malignancy may initiate the scleroderma-specific immune response and drive disease in a subset of scleroderma patients. [source]


    Nucleic acid sensing receptors in systemic lupus erythematosus: development of novel DNA- and/or RNA-like analogues for treating lupus

    CLINICAL & EXPERIMENTAL IMMUNOLOGY, Issue 2 2010
    P. Lenert
    Summary Double-stranded (ds) DNA, DNA- or RNA-associated nucleoproteins are the primary autoimmune targets in SLE, yet their relative inability to trigger similar autoimmune responses in experimental animals has fascinated scientists for decades. While many cellular proteins bind non-specifically negatively charged nucleic acids, it was discovered only recently that several intracellular proteins are involved directly in innate recognition of exogenous DNA or RNA, or cytosol-residing DNA or RNA viruses. Thus, endosomal Toll-like receptors (TLR) mediate responses to double-stranded RNA (TLR-3), single-stranded RNA (TLR-7/8) or unmethylated bacterial cytosine (phosphodiester) guanine (CpG)-DNA (TLR-9), while DNA-dependent activator of IRFs/Z-DNA binding protein 1 (DAI/ZBP1), haematopoietic IFN-inducible nuclear protein-200 (p202), absent in melanoma 2 (AIM2), RNA polymerase III, retinoic acid-inducible gene-I (RIG-I) and melanoma differentiation-associated gene 5 (MDA5) mediate responses to cytosolic dsDNA or dsRNA, respectively. TLR-induced responses are more robust than those induced by cytosolic DNA- or RNA- sensors, the later usually being limited to interferon regulatory factor 3 (IRF3)-dependent type I interferon (IFN) induction and nuclear factor (NF)-,B activation. Interestingly, AIM2 is not capable of inducing type I IFN, but rather plays a role in caspase I activation. DNA- or RNA-like synthetic inhibitory oligonucleotides (INH-ODN) have been developed that antagonize TLR-7- and/or TLR-9-induced activation in autoimmune B cells and in type I IFN-producing dendritic cells at low nanomolar concentrations. It is not known whether these INH-ODNs have any agonistic or antagonistic effects on cytosolic DNA or RNA sensors. While this remains to be determined in the future, in vivo studies have already shown their potential for preventing spontaneous lupus in various animal models of lupus. Several groups are exploring the possibility of translating these INH-ODNs into human therapeutics for treating SLE and bacterial DNA-induced sepsis. [source]