232 research outputs found

    Heritage language anxiety and majority language anxiety among Turkish immigrants in the Netherlands

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    Aims and objectives: This study examines the language anxiety that occurs in immigrants’ daily lives when speaking the heritage language and the majority language, both in their host country and during visits to their home country. It compares the levels of heritage language anxiety and majority language anxiety across three generations of the Turkish immigrant community in the Netherlands and explores the link between immigrants’ language anxiety, and sociobiographical (i.e. generation, gender, education) and language background variables (i.e. age of acquisition, self-perceived proficiency, frequency of language use). Design: A Likert scale-based questionnaire was administered to 116 participants across three generations who reported their language anxiety levels when speaking the heritage language and the majority language in three social contexts (i.e. family, friendship and speaking with native speakers). Findings: Statistical analyses revealed that heritage language anxiety and majority language anxiety were prevalent in immigrants’ daily life, and that levels of both forms of anxiety differed across generations, and in different daily life situations. First- and second-generation immigrants typically experienced majority language anxiety, while second- and predominantly third-generation immigrants suffered from heritage language anxiety. Relationships emerged between language background variables and both forms of anxiety, but only in certain situations. These findings suggest that language background variables on their own may be insufficient to explain immigrant language anxiety in certain social contexts (i.e. within family). Rather than merely language background factors, a variety of other issues within social, cultural and national currents must be considered when examining language anxiety in the immigrant context. Implications: Taking an interdisciplinary approach that combines language contact and foreign language anxiety/second language anxiety research, this study suggests that the concept of foreign language anxiety/second language anxiety should be expanded beyond the confines of the classroom in order to include daily interactions immigrant or minority communities. Originality: This study contributes to the limited body of evidence on the topic of language anxiety in immigrant contexts and presents a new construct ‘majority language anxiety’

    Addressing statistical biases in nucleotide-derived protein databases for proteogenomic search strategies

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    [Image: see text] Proteogenomics has the potential to advance genome annotation through high quality peptide identifications derived from mass spectrometry experiments, which demonstrate a given gene or isoform is expressed and translated at the protein level. This can advance our understanding of genome function, discovering novel genes and gene structure that have not yet been identified or validated. Because of the high-throughput shotgun nature of most proteomics experiments, it is essential to carefully control for false positives and prevent any potential misannotation. A number of statistical procedures to deal with this are in wide use in proteomics, calculating false discovery rate (FDR) and posterior error probability (PEP) values for groups and individual peptide spectrum matches (PSMs). These methods control for multiple testing and exploit decoy databases to estimate statistical significance. Here, we show that database choice has a major effect on these confidence estimates leading to significant differences in the number of PSMs reported. We note that standard target:decoy approaches using six-frame translations of nucleotide sequences, such as assembled transcriptome data, apparently underestimate the confidence assigned to the PSMs. The source of this error stems from the inflated and unusual nature of the six-frame database, where for every target sequence there exists five “incorrect” targets that are unlikely to code for protein. The attendant FDR and PEP estimates lead to fewer accepted PSMs at fixed thresholds, and we show that this effect is a product of the database and statistical modeling and not the search engine. A variety of approaches to limit database size and remove noncoding target sequences are examined and discussed in terms of the altered statistical estimates generated and PSMs reported. These results are of importance to groups carrying out proteogenomics, aiming to maximize the validation and discovery of gene structure in sequenced genomes, while still controlling for false positives

    Genome editing reveals a role for OCT4 in human embryogenesis.

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    Despite their fundamental biological and clinical importance, the molecular mechanisms that regulate the first cell fate decisions in the human embryo are not well understood. Here we use CRISPR-Cas9-mediated genome editing to investigate the function of the pluripotency transcription factor OCT4 during human embryogenesis. We identified an efficient OCT4-targeting guide RNA using an inducible human embryonic stem cell-based system and microinjection of mouse zygotes. Using these refined methods, we efficiently and specifically targeted the gene encoding OCT4 (POU5F1) in diploid human zygotes and found that blastocyst development was compromised. Transcriptomics analysis revealed that, in POU5F1-null cells, gene expression was downregulated not only for extra-embryonic trophectoderm genes, such as CDX2, but also for regulators of the pluripotent epiblast, including NANOG. By contrast, Pou5f1-null mouse embryos maintained the expression of orthologous genes, and blastocyst development was established, but maintenance was compromised. We conclude that CRISPR-Cas9-mediated genome editing is a powerful method for investigating gene function in the context of human development.DW was supported by the National Institute for Health Research (NIHR) Oxford Biomedical Research Centre Programme. NK was supported by the University of Oxford Clarendon Fund. AB was supported by a British Heart Foundation PhD Studentship (FS/11/77/39327). LV was supported by core grant funding from the Wellcome Trust and Medical Research Council (PSAG028). J-SK was supported by the Institute for Basic Science (IBS-R021-D1). Work in the KKN and JMAT labs was supported by the Francis Crick Institute which receives its core funding from Cancer Research UK, the UK Medical Research Council, and the Wellcome Trust (FC001120 and FC001193)

    Synthesis of Janus compounds for the recognition of G-U mismatched nucleobase pairs

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    The design and synthesis of two Janus-type heterocycles with the capacity to simultaneously recognize guanine and uracyl in G-U mismatched pairs through complementary hydrogen bond pairing is described. Both compounds were conveniently functionalized with a carboxylic function and efficiently attached to a tripeptide sequence by using solid-phase methodologies. Ligands based on the derivatization of such Janus compounds with a small aminoglycoside, neamine, and its guanidinylated analogue have been synthesized, and their interaction with Tau RNA has been investigated by using several biophysical techniques, including UV-monitored melting curves, fluorescence titration experiments, and 1H NMR. The overall results indicated that Janus-neamine/guanidinoneamine showed some preference for the +3 mutated RNA sequence associated with the development of some tauopathies, although preliminary NMR studies have not confirmed binding to G-U pairs. Moreover, a good correlation has been found between the RNA binding affinity of such Janus-containing ligands and their ability to stabilize this secondary structure upon complexation

    Poly(ADP-ribose) polymerase inhibition: a new direction for BRCA and triple-negative breast cancer?

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    Inhibitors of poly(ADP-ribose) polymerase (PARP)-mediated DNA repair have shown promise in early clinical studies in the treatment of specific subgroups of breast cancer. Notably, phase II trials indicate that olaparib, an oral PARP inhibitor, has activity as a single agent in BRCA-related tumours, and that a combination of iniparib, an intravenous PARP inhibitor, and chemotherapy offers a survival advantage, compared with chemotherapy alone, in triple-negative breast cancer. Phase III data on the latter indication are expected in 2011. Intriguingly, iniparib does not increase toxicity when used as a chemo-potentiating agent, suggesting that it differs in its mechanism of action from other agents in this class. Overall, PARP inhibitors represent a potentially important new class of anti-cancer agents with two potential modes of action, as single agents causing synthetic lethality and as chemo-potentiating agents

    The relationship between early neural responses to emotional faces at age 3 and later autism and anxiety symptoms in adolescents with autism

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    Both autism spectrum (ASD) and anxiety disorders are associated with atypical neural and attentional responses to emotional faces, differing in affective face processing from typically developing peers. Within a longitudinal study of children with ASD (23 male, 3 female), we hypothesized that early ERPs to emotional faces would predict concurrent and later ASD and anxiety symptoms. Greater response amplitude to fearful faces corresponded to greater social communication difficulties at age 3, and less improvement by age 14. Faster ERPs to neutral faces predicted greater ASD symptom improvement over time, lower ASD severity in adolescence, and lower anxiety in adolescence. Early individual differences in processing of emotional stimuli likely reflect a unique predictive contribution from social brain circuitry early in life

    Identification of PRRT2 as the causative gene of paroxysmal kinesigenic dyskinesias

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    Paroxysmal kinesigenic dyskinesias is a paroxysmal movement disorder characterized by recurrent, brief attacks of abnormal involuntary movements induced by sudden voluntary movements. Although several loci, including the pericentromeric region of chromosome 16, have been linked to paroxysmal kinesigenic dyskinesias, the causative gene has not yet been identified. Here, we identified proline-rich transmembrane protein 2 (PRRT2) as a causative gene of paroxysmal kinesigenic dyskinesias by using a combination of exome sequencing and linkage analysis. Genetic linkage mapping with 11 markers that encompassed the pericentromeric of chromosome 16 was performed in 27 members of two families with autosomal dominant paroxysmal kinesigenic dyskinesias. Then, the whole-exome sequencing was performed in three patients from these two families. By combining the defined linkage region (16p12.1–q12.1) and the results of exome sequencing, we identified an insertion mutation c.649_650InsC (p.P217fsX7) in one family and a nonsense mutation c.487C>T (p.Q163X) in another family. To confirm our findings, we sequenced the exons and flanking introns of PRRT2 in another three families with paroxysmal kinesigenic dyskinesias. The c.649_650InsC (p.P217fsX7) mutation was identified in two of these families, whereas a missense mutation, c.796C>T (R266W), was identified in another family with paroxysmal kinesigenic dyskinesias. All of these mutations completely co-segregated with the phenotype in each family. None of these mutations was identified in 500 normal unaffected individuals of matched geographical ancestry. Thus, we have identified PRRT2 as the first causative gene of paroxysmal kinesigenic dyskinesias, warranting further investigations to understand the pathogenesis of this disorder

    Genotype-Phenotype Correlation in NF1: Evidence for a More Severe Phenotype Associated with Missense Mutations Affecting NF1 Codons 844–848

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    Neurofibromatosis type 1 (NF1), a common genetic disorder with a birth incidence of 1:2,000–3,000, is characterized by a highly variable clinical presentation. To date, only two clinically relevant intragenic genotype-phenotype correlations have been reported for NF1 missense mutations affecting p.Arg1809 and a single amino acid deletion p.Met922del. Both variants predispose to a distinct mild NF1 phenotype with neither externally visible cutaneous/plexiform neurofibromas nor other tumors. Here, we report 162 individuals (129 unrelated probands and 33 affected relatives) heterozygous for a constitutional missense mutation affecting one of five neighboring NF1 codons—Leu844, Cys845, Ala846, Leu847, and Gly848—located in the cysteine-serine-rich domain (CSRD). Collectively, these recurrent missense mutations affect ∼0.8% of unrelated NF1 mutation-positive probands in the University of Alabama at Birmingham (UAB) cohort. Major superficial plexiform neurofibromas and symptomatic spinal neurofibromas were more prevalent in these individuals compared with classic NF1-affected cohorts (both p < 0.0001). Nearly half of the individuals had symptomatic or asymptomatic optic pathway gliomas and/or skeletal abnormalities. Additionally, variants in this region seem to confer a high predisposition to develop malignancies compared with the general NF1-affected population (p = 0.0061). Our results demonstrate that these NF1 missense mutations, although located outside the GAP-related domain, may be an important risk factor for a severe presentation. A genotype-phenotype correlation at the NF1 region 844–848 exists and will be valuable in the management and genetic counseling of a significant number of individuals
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