Search results for " Double-Stranded"
showing 10 items of 45 documents
RNA interference in Lepidoptera: an overview of successful and unsuccessful studies and implications for experimental design.
2011
International audience; Gene silencing through RNA interference (RNAi) has revolutionized the study of gene function, particularly in non-model insects. However, in Lepidoptera (moths and butterflies) RNAi has many times proven to be difficult to achieve. Most of the negative results have been anecdotal and the positive experiments have not been collected in such a way that they are possible to analyze. In this review, we have collected detailed data from more than 150 experiments including all to date published and many unpublished experiments. Despite a large variation in the data, trends that are found are that RNAi is particularly successful in the family Saturniidae and in genes involv…
Specific and highly efficient condensation of GC and IC DNA by polyaza pyridinophane derivatives
2018
Abstract Two bis-polyaza pyridinophane derivatives and their monomeric reference compounds revealed strong interactions with ds-DNA and RNA. The bis-derivatives show a specific condensation of GC- and IC-DNA, which is almost two orders of magnitude more efficient than the well-known condensation agent spermine. The type of condensed DNA was identified as ψ-DNA, characterized by the exceptionally strong CD signals. At variance to the almost silent AT(U) polynucleotides, these strong CD signals allow the determination of GC-condensates at nanomolar nucleobase concentrations. Detailed thermodynamic characterisation by ITC reveals significant differences between the DNA binding of the bis-deriv…
A Comparison of Techniques to Evaluate the Effectiveness of Genome Editing
2018
Genome editing using engineered nucleases (meganucleases, zinc finger nucleases, transcription activator-like effector nucleases) has created many recent breakthroughs. Prescreening for efficiency and specificity is a critical step prior to using any newly designed genome editing tool for experimental purposes. The current standard screening methods of evaluation are based on DNA sequencing or use mismatch-sensitive endonucleases. They can be time-consuming and costly or lack reproducibility. Here, we review and critically compare standard techniques with those more recently developed in terms of reliability, time, cost, and ease of use.
From “Cellular” RNA to “Smart” RNA: Multiple Roles of RNA in Genome Stability and Beyond
2018
Coding for proteins has been considered the main function of RNA since the "central dogma" of biology was proposed. The discovery of noncoding transcripts shed light on additional roles of RNA, ranging from the support of polypeptide synthesis, to the assembly of subnuclear structures, to gene expression modulation. Cellular RNA has therefore been recognized as a central player in often unanticipated biological processes, including genomic stability. This ever-expanding list of functions inspired us to think of RNA as a "smart" phone, which has replaced the older obsolete "cellular" phone. In this review, we summarize the last two decades of advances in research on the interface between RNA…
In vitro model for DNA double‐strand break repair analysis in breast cancer reveals cell type–specific associations with age and prognosis
2016
Dysfunction of homologous recombination is a common denominator of changes associated with breast cancer-predisposing mutations. In our previous work, we identified a functional signature in peripheral blood lymphocytes from women who were predisposed that indicated a shift from homologous recombination to alternative, error-prone DNA double-strand break (DSB) repair pathways. To capture both hereditary and nonhereditary factors, we newly established a protocol for isolation and ex vivo analysis of epithelial cells, epithelial-mesenchymal transition cells (EMTs), and fibroblasts from breast cancer specimens (147 patients). By applying a fluorescence-based test system, we analyzed the error-…
Impairment of intracellular antiviral defense with age: age-dependent changes in expression of interferon-induced and double-stranded RNA-activated 2…
1995
The 2',5'-oligoadenylate (2-5A) system is involved in the defense of mammalian cells against virus infection. In a previous study [25], we demonstrated that the activities of the enzymes which synthesize and degrade 2-5A [2-5A synthetase (2-5OAS) and 2',3'-exoribonuclease] and of the enzyme that is activated by 2-5A (ribonuclease L) change during aging and development in different tissues of rat. The age-dependent decrease in 2-5OAS activity and increase in 2-5A nuclease activity results in a decrease in the cellular 2-5A content, suggesting that the efficiency of the antiviral 2-5A system is impaired in aged rats. Here we determined the age-dependent changes in the level of mRNA coding for…
Senataxin defective in ataxia oculomotor apraxia type 2 is involved in the defence against oxidative DNA damage
2007
Adefective response to DNA damage is observed in several human autosomal recessive ataxias with oculomotor apraxia, including ataxia-telangiectasia. We report that senataxin, defective in ataxia oculomotor apraxia (AOA) type 2, is a nuclear protein involved in the DNA damage response. AOA2 cells are sensitive to H2O2, camptothecin, and mitomycin C, but not to ionizing radiation, and sensitivity was rescued with full-length SETX cDNA. AOA2 cells exhibited constitutive oxidative DNA damage and enhanced chromosomal instability in response to H2O2. Rejoining of H2O2-induced DNA double-strand breaks (DSBs) was significantly reduced in AOA2 cells compared to controls, and there was no evidence fo…
The size of aryl linker between two polyaza-cyclophane moieties controls the binding selectivity to ds-RNA vs ds-DNA
2013
Aryl-linked (pyridine- vs. phenanthroline-) bis-polyaza pyridinophane scorpiands PYPOD and PHENPOD strongly bind to the double stranded DNA and RNA, whereby very intriguing RNA over DNA selectivity is finely tuned by aryl-linker length and aromatic surface. Moreover, PYPOD and PHENPOD dimer formation at high compound/polynucleotide ratios is highly sensitive to the fine interplay between the steric and binding properties of compound-dimers and the DNA minor groove/RNA major groove. That is demonstrated by significantly different induced CD spectra, which allow spectroscopic differentiation between various DNA/RNA secondary structures. A significantly higher (micromolar) antiproliferative ef…
Artesunate induces oxidative DNA damage, sustained DNA double-strand breaks, and the ATM/ATR damage response in cancer cells.
2011
Abstract Artesunate, the active agent from Artemisia annua L. used in the traditional Chinese medicine, is being applied as a first-line drug for malaria treatment, and trials are ongoing that include this drug in cancer therapy. Despite increasing interest in its therapeutic application, the mode of cell killing provoked by artesunate in human cells is unknown. Here, we show that artesunate is a powerful inducer of oxidative DNA damage, giving rise to formamidopyrimidine DNA glycosylase–sensitive sites and the formation of 8-oxoguanine and 1,N6-ethenoadenine. Oxidative DNA damage was induced in LN-229 human glioblastoma cells dose dependently and was paralleled by cell death executed by ap…
Temozolomide- and fotemustine-induced apoptosis in human malignant melanoma cells: response related to MGMT, MMR, DSBs, and p53
2009
Malignant melanomas are highly resistant to chemotherapy. First-line chemotherapeutics used in melanoma therapy are the methylating agents dacarbazine (DTIC) and temozolomide (TMZ) and the chloroethylating agents BCNU and fotemustine. Here, we determined the mode of cell death in 11 melanoma cell lines upon exposure to TMZ and fotemustine. We show for the first time that TMZ induces apoptosis in melanoma cells, using therapeutic doses. For both TMZ and fotemustine apoptosis is the dominant mode of cell death. The contribution of necrosis to total cell death varied between 10 and 40%. The O(6)-methylguanine-DNA methyltransferase (MGMT) activity in the cell lines was between 0 and 1100 fmol m…