281 research outputs found

    Deep-intronic ATM mutation detected by genomic resequencing and corrected in vitro by antisense morpholino oligonucleotide (AMO)

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    Recent development of next-generation DNA sequencing (NGS) techniques is changing the approach to search for mutations in human genetic diseases. We applied NGS to study an A-T patient in which one of the two expected mutations was not found after DHPLC, cDNA sequencing and MLPA screening. The 160-kb ATM genomic region was divided into 31 partially overlapping fragments of 4–6 kb and amplified by long-range PCR in the patient and mother, who carried the same mutation by segregation. We identified six intronic variants that were shared by the two genomes and not reported in the dbSNP(132) database. Among these, c.1236-405C>T located in IVS11 was predicted to be pathogenic because it affected splicing. This mutation creates a cryptic novel donor (5â€Č) splice site (score 1.00) 405 bp upstream of the exon 12 acceptor (3â€Č) splice site. cDNA analysis showed the inclusion of a 212-bp non-coding ‘pseudoexon' with a premature stop codon. We validated the functional effect of the splicing mutation using a minigene assay. Using antisense morpholino oligonucleotides, designed to mask the cryptic donor splice-site created by the c.1236-405C>T mutation, we abrogated the aberrant splicing product to a wild-type ATM transcript, and in vitro reverted the functional ATM kinase impairment of the patients' lymphoblasts. Resequencing is an effective strategy for identifying rare splicing mutations in patients for whom other mutation analyses have failed (DHPLC, MLPA, or cDNA sequencing). This is especially important because many of these patients will carry rare splicing variants that are amenable to antisense-based correction

    A New Series of Small Molecular Weight Compounds Induce Read Through of All Three Types of Nonsense Mutations in the ATM Gene

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    Chemical-induced read through of premature stop codons might be exploited as a potential treatment strategy for genetic disorders caused by nonsense mutations. Despite the promise of this approach, only a few read-through compounds (RTCs) have been discovered to date. These include aminoglycosides (e.g., gentamicin and G418) and nonaminoglycosides (e.g., PTC124 and RTC13). The therapeutic benefits of these RTCs remain to be determined. In an effort to find new RTCs, we screened an additional ~36,000 small molecular weight compounds using a high-throughput screening (HTS) assay that we had previously developed and identified two novel RTCs, GJ071, and GJ072. The activity of these two compounds was confirmed in cells derived from ataxia telangiectasia (A-T) patients with three different types of nonsense mutation in the ATM gene. Both compounds showed activity comparable to stop codons (TGA, TAG, and TAA) PTC124 and RTC13. Early structure-activity relationship studies generated eight active analogs of GJ072. Most of those analogs were effective on all three stop codons. GJ071 and GJ072, and some of the GJ072 analogs, appeared to be well tolerated by A-T cells. We also identified another two active RTCs in the primary screen, RTC204 and RTC219, which share a key structural feature with GJ072 and its analogs

    Intermolecular rovibrational bound states of H2O–H2 dimer from a multiconfiguration time dependent Hartree approach

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    We compute the rovibrational eigenstates of the H2O–H2 Van der Waals complex using the accurate rigid-rotor potential energy surface of Valiron et al. (2008) with the MultiConfiguration Time Dependent Hartree (MCTDH) method. The J=0–2 rovibrational bound states calculations are done with the Block Improved Relaxation procedure of MCTDH and the subsequent assignment of the states is achieved by inspection of the wavefunctions’ properties. The results of this work are found to be in close agreement with previous time independent calculations reported for this complex and therefore supports the use of the MCTDH approach for the rovibrational spectroscopic study of such weakly bound complexes

    Impact of DNA ligase IV on nonhomologous end joining pathways during class switch recombination in human cells

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    Class switch recombination (CSR) is a region-specific, transcriptionally regulated, nonhomologous recombinational process that is initiated by activation-induced cytidine deaminase (AID). The initial lesions in the switch (S) regions are subsequently processed and resolved, leading to recombination of the two targeted S regions. The mechanisms by which repair and ligation of the broken DNA ends occurs is still elusive. Recently, a small number of patients lacking DNA ligase IV, a critical component of the nonhomologous end joining (NHEJ) machinery, have been identified. We show that these patients display a considerably increased donor/acceptor homology at SΌ–Sα junctions compared with healthy controls. In contrast, SΌ–SÎł junctions show an increased frequency of insertions but no increase in junctional homology. These altered patterns of junctional resolution may be related to differences in the homology between the SÎŒ and the downstream isotype S regions, and could reflect different modes of switch junction resolution when NHEJ is impaired. These findings link DNA ligase IV, and thus NHEJ, to CSR

    From quantum to classical images

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    We display the results of the numerical simulations of a set of Langevin equations, which describe the dynamics of a degenerate optical parametric oscillator in the Wigner representation. The scan of the threshold region shows the gradual transformation of a quantum image into a classical roll pattern. An experiment on parametric down-conversion in lithium triborate shows strikingly similar results in both the near and the far field, displaying qualitatively the classical features of quantum images

    Quantifying methane vibrational and rotational temperature with Raman scattering

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    This work describes the theoretical basis and implementation of the measurement of vibrational (T vib) and rotational (T rot) temperatures in CH4 by fitting spontaneous Raman scattering spectra in the Pentad region. This method could be applied for thermal equilibrium temperature measurements applications, e.g. in combustion, or vibrational-rotational non-equilibrium applications, such as in plasma chemistry. The method of calculating these temperatures is validated against known temperature thermal equilibrium spectra up to 860 K from published data, giving an estimated relative error of 10%. This demonstrates that both the calculated stick spectrum and the algorithm to determine T vib and T rot for CH4 is robust to 860 K, but we expect it is valid to 1500 K. Additionally, a number of non-equilibrium spectra generated with a pulsed microwave plasma are fitted to find T vib and T rot, further demonstrating the applicability of this method in fitting non-equilibrium spectra.</p
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