1,721,014 research outputs found
Non-canonical translation start sites in the TMEM16A chloride channel
No full textAbstractTMEM16A is a plasma membrane protein with voltage- and calcium-dependent chloride channel activity. The role of the various TMEM16A domains in expression and function is poorly known. In a previous study, we found that replacing the first ATG of the TMEM16A coding sequence with a nonsense codon (M1X mutation), to force translation from the second ATG localized at position 117, only had minor functional consequences. Therefore, we concluded that this region is dispensable for TMEM16A processing and channel activity. We have now removed the first 116 codons from the TMEM16A coding sequence. Surprisingly, the expression of the resulting mutant, Δ(1–116), resulted in complete loss of activity. We hypothesized that, in the mutant M1X, translation may start at a position before the second ATG, using a non-canonical start codon. Therefore, we placed an HA-epitope at position 89 in the M1X mutant. We found, by western blot analysis, that the HA-epitope can be detected, thus demonstrating that translation starts from an upstream non-ATG codon. We truncated the N-terminus of TMEM16A at different sites while keeping the HA-epitope. We found that stepwise shortening of TMEM16A caused an in parallel stepwise decrease in TMEM16A expression and function. Our results indicate that indeed the N-terminus of TMEM16A is important for its activity. The use of an alternative start codon appears to occur in a naturally-occurring TMEM16A isoform that is particularly expressed in human testis. Future experiments will need to address the role of normal and alternative amino-terminus in TMEM16A structure and function
Distribution and Characterization of ANO10 in Mouse Small Intestine
Full text linkBackground: Anoctamin 10 (Ano10) belongs to the class of proteins that includes Ca2+ activated Cl-channels such as Ano1, which is expressed in interstitial cells of Cajal (ICC). Mutations in Ano10 lead to spinocerebellar ataxia and immunological defects. Evidence suggests that Ano10 is not a Ca2+ -activated Cl-channel but rather an intracellular protein that may regulate intracellular Ca2+. The aim of this study was to characterize the distribution of Ano10 in the mouse small intestine in order to determine the cell types in which Ano10 may contribute to cellular physiology.
Methods: Small intestinal tissues from adult Balb/c (n=3) mice were obtained for both cryosections (10 μm thickness) and whole mount preparations. Tissues were immunolabeled using antibodies raised against Ano10 (rabbit polyclonal), a marker of ICC - Kit (goat polyclonal), a pan-neuronal marker - HuC/D (human, serum derived), and a macrophage marker - F4/80 (rat monoclonal). Secondary antibody controls were performed by exposing samples to secondary antibody in the absence of primary antibody to test for non-specific staining. Double labeling of Ano10 with other cell specific markers was performed on 5 cryosections and 2 whole mounts for each mouse. The distribution of immunoreactivity (IR) was determined by confocal microscopic imaging.
Results: Ano10-IR was found to be present in neuronal cell bodies outside of the nucleus. Ano10-IR was present in 100% of HuC/D-positive neurons of the myenteric and submucosal plexuses. Ano10-IR was not found in ICC of the myenteric region; however, there was colocalization of Ano10-IR with Kit-IR on ICC of the deep muscularis plexus (ICC-DMP). Ano10-IR also colocalized with F4/80-IR present on resident macrophages in the region of the myenteric plexus. 100% of F4/80-IR colocalized with Ano10-IR.
Conclusions: Immuno-reactivity for Ano10 is present in all types of myenteric and submucosal neurons and in all resident macrophages. Ano10-IR was present in a subset of ICC, specifically ICC-DMP but not ICC in the myenteric plexus. Given the putative role of Ano10 as a regulator of intracellular Ca2+, Ano10 may play a role both in regulation of gastrointestinal motility via neurons and ICC-DMP, as well as immunological responses via resident macrophages.
Grant support: NIH DK057061, P01DK68055, and P30DK08456
Distribution and Characterization of RAD21 Immunoreactivity in Mouse and Human Enteric Neurons
No full text
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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