1,720,977 research outputs found
A developmental switch in microglial HDAC function
No full textThe epigenetic mechanisms controlling microglia functions are largely unknown. In this issue of Immunity, Datta et al. (2018) uncover surprising and distinct effects of deleting the epigenetic regulators HDAC1 and HDAC2 during microglial development versus during the course of neurodegeneration
The role of GW182 proteins in microRNA-mediated gene silencing
Full text linkMicroRNAs are endogenous approximately 21-nucleotide-long non-coding RNAs that act as post-transcriptional regulators of gene expression by base pairing to target mRNAs. Mature miRNAs form part of ribonucleoprotein complexes, called miRNA-induced silencing complexes (miRISCs), that contain Argonaute (AGO) and GW182 as core proteins. Drosophila melanogaster contains only one GW182 protein (DmGW182) but there are three GW182 paralogs, TNRC6A, TNRC6B, and TNRC6C, encoded in mammalian genomes. Proteins of the GW182 family play an important role in the execution of miRNA-mediated repression. However, the molecular mechanism of GW182-mediated repression is not entirely understood.
In order to get a more comprehensive understanding of the mechanism of miRNA-mediated repression, we studied the function of GW182 proteins using human HEK293 cells and Drosophila S2 cells as model systems. As a result of these investigations, we identified the C-terminal fragment of the human GW182 protein TNRC6C (CED) as a key region mediating miRNA-induced repression by interacting with PABP via its PAM2 motif and by recruiting the PAN2-PAN3 and CCR4-CAF1-NOT deadenylase complexes via conserved tryptophan-containing motifs (W-motifs).
In addition, tethering assays in HEK293 cells and Drosophila S2 cells revealed that the C-terminal regions of GW182 proteins are able to repress not only polyadenylated but also poly(A)-free mRNAs. Interestingly, the W-motifs which are essential for interaction of the CED with the CCR4-CAF1-NOT complex, were also required for the repression of poly(A)-free mRNAs by the tethered CEDs of human TNRC6C and DmGW182. Indeed, direct tethering of CCR4-CAF1-NOT complex components in HEK293 or S2 cells repressed not only polyadenylated but also poly(A)-free mRNAs and the RNA levels of poly(A)-free mRNAs were either not affected or only slightly reduced, indicating that the major part of the repression was due to inhibition of translation. Finally, repression of poly(A)-free mRNAs in Drosophila S2 cells by tethered DmGW182 or its CED depended on NOT1 but repression by tethered CAF1 or CNOT1 was independent of GW182, indicating that NOT1 acts downstream of GW182 in the repression of poly(A)-free mRNAs.
Taken together, these data indicate that recruitment of the CCR4-CAF1-NOT complex mediated by W-motifs of GW182 proteins, in addition to inducing deadenylation, also contributes to translational repression
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
Code for the Mathys, Boix, Akay et al., 2024 paper
No full text<p>Code for the Mathys, Boix, Akay et al., 2024 paper on single-cell atlas of AD progression across brain regions</p>
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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