1,720,960 research outputs found
ALTERNATIVE SPLICING AND PHOSPHORYLATION PROVIDE A MECHANISTIC BASIS FOR FUNCTIONAL SPECIALIZATION OF LSD1/KDM1 HISTONE DEMETHYLASE IN THE CENTRAL NERVOUS SYSTEM
No full textChromatin represents the physiological substrate of epigenetic regulation, underlying several biological processes, from replication and transcriptional activity to cell lineage commitment and adaptation in response to specific cues. In the central nervous system, chromatin integrates a plethora of converging signaling pathways, leading to short- and long-term changes in gene expression that are crucial for neuronal commitment, terminal differentiation and neuroplasticity throughout life. Although a variety of ubiquitously expressed chromatin-remodeling complexes assist tissue-specific transcription factors in mediating histotype-restricted transcriptional regulation, neuro restricted chromatin-remodeling factors have just been recently described.
Here, I report the identification of four mammal-specific variants of the histone demethylase LSD1 / KDM1 arising from combinatorial retention of two alternatively spliced exons, resulting in either ubiquitous isoforms or neuro-restricted ones, which are dynamically regulated during cortical development. The neuro-specific variants, whose functional diversification partly relies on the phosphorylation status, contribute to the acquisition of neurite morphology in an exclusive way.
The expression of LSD1 splice variants is particularly regulated during perinatal stages, with a progressive increase of LSD1 neuro-specific isoforms over the ubiquitous ones and the same LSD1 splice dynamics can be fairly recapitulated in cultured cortical neurons reflecting the early synaptic establishment. While LSD1 isoforms exhibit a comparable demethylase activity in vitro, the sole neuro-specific isoforms display an altered repressor activity on a reporter gene in cortical neurons, where their overexpression enhances neurite morphogenesis. Conversely, the imbalance of LSD1 isoforms that are devoid of the neurospecific exon elicits no morphogenic effect, indicating that the arousal of neuronal LSD1 isoforms pace-makes early neurite morphogenesis. The genome wide-location of LSD1 in cortical neurons by chromatin immunoprecipitation sequencing reveals its extensive role in the regulation of promoters related to developmental processes, pattern specification and forebrain organogenesis, as well as the control of cell fate decisions and calcium induced neuronal signaling, confirming its neurogenic implication.
Furthermore, for those genes where multiple binding locations can be found at short and long distance from the same transcriptional start site, a wide-range LSD1 regulatory role can be hypothesized, possibly related to enhancers function
Alternative splicing in the mammalian nervous system endows the histone demethylase LSD1-KDM1 of the ability to induce neurite morphogenesis
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
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
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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