1,721,135 research outputs found

    Alternative splicing: good and bad effects of translationally silent substitutions

    No full text
    Nucleotide variations that do not alter the protein-coding sequence have been routinely considered as neutral. In light of the developments we have seen over the last decade or so in the RNA processing and translational field, it would be proper when assessing these variants to ask if this change is neutral, good or bad. This question has been recently partly addressed by genome-wide in silico analysis but significantly fewer cases by laboratory experimental examples. Of particular relevance is the effect these mutations have on the pre-mRNA splicing pattern. In fact, alterations in this process may occur as a consequence of translationally silent mutations leading to the expression of novel splicing isoforms and/or loss of an existing one. This phenomenon can either generate new substrates for evolution or cause genetic disease when aberrant isoforms altering the essential protein function are produced. In this review we briefly describe the current understanding in the field and discuss emerging directions in the study of the splicing mechanism by integrating disease-causing splicing mutations and evolutionary change

    Functional splicing assay shows a pathogenic intronic mutation in neurofibromatosis type 1 (NF1) due to intronic sequence exonization

    No full text
    Genomic variations with no apparent effect ("neutral polymorphisms") may have a significant effect on splicing. The effect of this type of mutation is difficult to spot, unless a functional assay is undertaken. In our study, DNA sequencing of a patient with clinically defined neurofibromatosis type 1 (NF1) showed only a single polymorphism in intron 30 due to an A>G transition 279 nucleotides from the 3' splice site. Using a minigene splicing assay we conclusively show that this change produces a cryptic exon with a 3' SS defined by the nucleotide change and the unexpected activation of a very weak 5'SS. Further site directed mutagenesis studies aimed at identifying the signals involved in the cryptic exon inclusion were carried out. Interestingly we find that particular characteristics of the cryptic 5' SS are essential for its inclusion. Significantly an additional single nucleotide change disrupting the cryptic 5'ss consensus sequence rescues the effect of the pathogenetic mutation resulting in normal splicing

    Going Beyond Counting First Authors in Author Co-citation Analysis

    Full text link
    The present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed

    Contaminazione batterica in un impianto di dialisi

    No full text
    After a brief review about the principal risks of infection caused by the application of dialysis, the Authors describe the results relative to the control of the bacteriological contamination present in a dialysis unit of a large Roman hospital. The results showed a general compliance with the guidelines. However the older models of the apparatus were found to be more contaminated than the more up to date models and the contamination risk was higher in correspondence with connections of the apparatus. Furthermore the presence of opportunistic microrganisms such as P aeruginosa suggests the need for their substitution

    Variations on the Author

    Full text link
    “Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
    corecore