1,720,966 research outputs found
A novel Yap/Taz zebrafish reporter reveals a role of Hippo pathway transducers in angiogenesis
Get PDFYAP and TAZ, by orchestrating cell proliferation, cell death and cell-fate decisions, are key players of a complex network of signaling pathways acting during development. Deregulation of YAP/TAZ signaling causes robust organ overgrowth during organogenesis, which translates to loss of tissue homeostasis in the adult and consequent cancer development. YAP/TAZ are transcriptional co-activators that interact with TEAD transcription factors to promote cell proliferation and survival. Their transcriptional activity is regulated by nucleocytoplasmic shuttling and nuclear accumulation, which are controlled by the Hippo kinase cascade, but also by mechanical cues sensed by the cell and by other pathways. Among these, Wnt/β-catenin takes on a particular relevance, since it was recently shown to regulate YAP/TAZ activity through AXIN-mediated sequestration of YAP/TAZ in the β-catenin destruction complex.
Here, we describe the generation, validation and characterization of a novel biosensor zebrafish reporting the activity of Yap/Taz. It expresses nuclear mCherry, eGFP or the destabilized green fluorescent protein VenusPEST under the control of a promoter fragment of the human YAP/TAZ target gene CTGF, that contains 3 TEAD DNA-binding sites. Several independent founder fish transmitting the transgene to the germline were identified and used to establish the stable reporter lines. All stable transgenic fish shared a similar expression pattern, which was maintained in subsequent generations. Knockdown and overexpression approaches were used to validate the reporter. Co-injection of two morpholinos targeting Yap and Taz pre-mRNAs reduced the reporter signal, whereas injection of mRNAs coding for a constitutively active form of Yap, Taz and Tead (YAP-5SA, TAZ-4SA, TEAD-VP16) increased it. The CTGF-based transgenic lines represent therefore bona fide Yap/Taz reporters.
During development, strong reporter signal is visible mainly in the lens and otic vesicles, the pharyngeal arches, the heart, the pectoral fin and the vasculature, but the reporter protein expression is also detected in many other tissues and organs. The almost ubiquitous activation of Yap/Taz observed during early embryogenesis, consistent with the general role of YAP/TAZ in promoting cell proliferation and organ growth, is largely silenced in the adult fish, where the reporter signal is restricted to the lens, the ovary, the heart and the whole vasculature. We also showed that the CTGF-based biosensor zebrafish is able to report Yap/Taz activation during larval and adult fin regeneration, as expected from the role that YAP/TAZ signaling plays in the regenerative processes.
The zebrafish CTGF-based reporter permitted to show in a living organism during development the regulation that the Wnt/β-catenin pathway exerts on Yap/Taz activity. Our results in terms of variations of the reporter signal, after both genetic and pharmacological modulation of the Wnt pathway activity, are in accordance with the model recently depicted in vitro.
The general and sustained reporter activity we observed in the endothelium during embryogenesis suggested a functional involvement of Yap/Taz signaling in developmental angiogenesis. Yap/Taz knockdown impaired the intersegmental vessels (ISVs) growth, while the overactivation of Yap/Taz-mediated transcription caused an aberrant sprouting from the ISVs. The vessel sprouting-promoting capacity of Yap/Taz is cell-autonomous, as the same phenomenon was observed by expressing TAZ-4SA under the control of an endothelium-specific promoter.
The CTGF-based zebrafish reporter is a new powerful tool to study in vivo Yap/Taz pathway activation, with possible applications in drug screening, regeneration and cancer biology. It permitted to confirm in vivo during development the crosstalk between Wnt/β-catenin and Yap/Taz pathways and to discover a novel role of Yap/Taz in vessel sprouting, suggesting a pro-angiogenic function of YAP/TAZ transcriptional activity
Time to fight: targeting the circadian clock molecular machinery in cancer therapy
No full textThe circadian clock regulates a wide range of molecular pathways and biological processes. The expression of clock genes is often altered in cancer, fostering tumor initiation and progression. Inhibition and activation of core circadian clock genes, as well as treatments that restore circadian rhythmicity, have been successful in counteracting tumor growth in different experimental models. Here, we provide an up-to-date overview of studies that show the therapeutic effects of targeting the clock molecular machinery in cancer, both genetically and pharmacologically. We also highlight future areas for progress that offer a promising path towards innovative anticancer strategies. Substantial limitations in the current understanding of the complex interplay between the circadian clock and cancer in vivo need to be addressed in order to allow clock-targeting therapies in cancer
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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