1,720,981 research outputs found
Circular RNAs expression and function in myogenesis
Get PDFSkeletal myogenesis is a well-characterized biological process driving the formation of the adult muscle tissue from mesodermal progenitors. The key molecular and cellular steps of such process can be replicated in vitro, by culturing muscle precursor cells called myoblasts, which can be induced to differentiate into mature myotubes. We characterized the role of a long non-coding RNA, linc-MD1, in regulating in vitro differentiation of murine myoblasts by acting as a molecular decoy for two microRNAs, miR-133 and miR-135, and we further dissected the regulation of linc-MD1 biosynthesis by the RNA binding protein HuR. Searching for new non-canonical RNA species involved in myogenesis, we directed our attention to circular RNAs (circRNAs). Circular RNAs are produced by the spliceosome via a particular reaction called back-splicing, which links a donor splice site to an upstream acceptor site, thereby generating a covalently closed RNA molecule. We performed high-throughput expression profiling of circRNAs in murine and human cells and studied the principles of their regulation during myogenesis. We then applied a high-content functional genomic screen of conserved circRNAs and found that these molecules are actively involved in the control of myoblasts differentiation. Among them, we further characterized circ-ZNF609 and found that it is able to control myoblast proliferation, providing the first example of a circular RNA involved in a relevant biological process. Moreover, sequence and biochemical analyses suggested that circ-ZNF609 might be translated in a functional protein, representing a possible molecular mechanism for circRNA function
Biogenesis and function of non-coding RNAs in muscle differentiation and in Duchenne muscular dystrophy
No full textIt is now becoming largely accepted that the non-coding portion of the genome, rather than its coding counterpart, is likely to account for the greater complexity of higher eukaryotes. Moreover, non-coding RNAs have been demonstrated to participate in regulatory circuitries that are crucial for development and differentiation. Whereas the biogenesis and function of small non-coding RNAs, particularly miRNAs (microRNAs), has been extensively clarified in many eukaryotic systems, very little is known about the long non-coding counterpart of the transcriptome. In the present review, we revise the current knowledge of how small non-coding RNAs and IncRNAs (long non-coding RNAs) impinge on circuitries controlling proper muscle differentiation and homoeostasis and how their biogenesis is regulated. Moreover, we provide new insights into an additional mechanism of post-transcriptional regulation mediated by IncRNAs, which, acting as miRNA 'sponges', have an impact on the distribution of miRNA molecules on their targets with features similar to those described for ceRNAs (competing endogenous RNAs).It is now becoming largely accepted that the non-coding portion of the genome, rather than its coding counterpart, is likely to account for the greater complexity of higher eukaryotes. Moreover, non-coding RNAs have been demonstrated to participate in regulatory circuitries that are crucial for development and differentiation. Whereas the biogenesis and function of small non-coding RNAs, particularly miRNAs (microRNAs), has been extensively clarified in many eukaryotic systems, very little is known about the long non-coding counterpart of the transcriptome. In the present review, we revise the current knowledge of how small non-coding RNAs and lncRNAs (long non-coding RNAs) impinge on circuitries controlling proper muscle differentiation and homoeostasis and how their biogenesis is regulated. Moreover, we provide new insights into an additional mechanism of post-transcriptional regulation mediated by lncRNAs, which, acting as miRNA 'sponges', have an impact on the distribution of miRN
Multifunctional system-on-glass for lab-on-chip applications
No full textLab-on-Chip are miniaturized systems able to perform biomolecular analysis in shorter time and with lower reagent consumption than a standard laboratory. Their miniaturization interferes with the multiple functions that the biochemical procedures require. In order to address this issue, our paper presents, for the first time, the integration on a single glass substrate of different thin film technologies in order to develop a multifunctional platform suitable for on-chip thermal treatments and on-chip detection of biomolecules. The proposed System on-Glass hosts thin metal films acting as heating sources; hydrogenated amorphous silicon diodes acting both as temperature sensors to monitor the temperature distribution and photosensors for the on-chip detection and a ground plane ensuring that the heater operation does not affect the photodiode currents. The sequence of the technological steps, the deposition temperatures of the thin films and the parameters of the photolithographic processes have been optimized in order to overcome all the issues of the technological integration. The device has been designed, fabricated and tested for the implementation of DNA amplification through the Polymerase Chain Reaction (PCR) with thermal cycling among three different temperatures on a single site. The glass has been connected to an electronic system that drives the heaters and controls the temperature and light sensors. It has been optically and thermally coupled with another glass hosting a microfluidic network made in polydimethylsiloxane that includes thermally actuated microvalves and a PCR process chamber. The successful DNA amplification has been verified off-chip by using a standard fluorometer
Circ-ZNF609 regulates G1-S progression in rhabdomyosarcoma
Get PDFCircular RNAs (circRNAs) represent a class of covalently closed RNAs, derived from non-canonical splicing events, which are expressed in all eukaryotes and often conserved among different species. We previously showed that the circRNA originating from the ZNF609 locus (circ-ZNF609) acts as a crucial regulator of human primary myoblast growth: indeed, the downregulation of the circRNA, and not of its linear counterpart, strongly reduced the proliferation rate of in vitro cultured myoblasts. To deepen our knowledge about circ-ZNF609 role in cell cycle regulation, we studied its expression and function in rhabdomyosarcoma (RMS), a pediatric skeletal muscle malignancy. We found that circ-ZNF609 is upregulated in biopsies from the two major RMS subtypes, embryonal (ERMS) and alveolar (ARMS). Moreover, we discovered that in an ERMS-derived cell line circ-ZNF609 knock-down induced a specific block at the G1-S transition, a strong decrease of p-Akt protein level and an alteration of the pRb/Rb ratio. Regarding p-Akt, we were able to show that circ-ZNF609 acts by counteracting p-Akt proteasome-dependent degradation, thus working as a new regulator of cell proliferation-related pathways. As opposed to ERMS-derived cells, the circRNA depletion had no cell cycle effects in ARMS-derived cells. Since in these cells the p53 gene resulted downregulated, with a concomitant upregulation of its cell cycle-related target genes, we suggest that this could account for the lack of circ-ZNF609 effect in ARMS. © 2019, The Author(s)
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
Exon skipping and duchenne muscular dystrophy therapy: selection of the most active U1 snRNA antisense able to induce dystrophin exon 51 skipping.
No full textOne promising approach for the gene therapy of Duchenne muscular dystrophy (DMD) is exon skipping. When thinking of possible intervention on human, it is very crucial to identify the most appropriate antisense sequences able to provide the highest possible skipping efficiency. In this article, we compared the exon 51 skipping activity of 10 different antisense molecules, raised against splice junctions and/or exonic splicing enhancers (ESEs), expressed as part of the U1 small nuclear RNA (snRNA). The effectiveness of each construct was tested in human DMD myoblasts carrying the deletion of exons 48-50, which can be treated with skipping of exon 51. Our results show that the highest skipping activity and dystrophin rescue is achieved upon expression of a U1 snRNA-derived antisense molecule targeting exon 51 splice sites in combination with an internal exon sequence. The efficacy of this molecule was further proven on an exon 45-50 deletion background, utilizing patient's fibroblasts transdifferentiated into myoblasts. In this system, we showed that the selected antisense was able to produce 50% skipping of exon 51
The miR-223 host non-coding transcript linc-223 induces IRF4 expression in acute myeloid leukemia by acting as a competing endogenous RNA
Get PDFAlterations in genetic programs required for terminal myeloid differentiation and aberrant proliferation characterize acute myeloid leukemia (AML) cells. Here, we identify the host transcript of miR-223, linc-223, as a novel functional long non-coding RNA (lncRNA) in AML. We show that from the primary nuclear transcript, the alternative production of miR-223 and linc-223 is finely regulated during monocytic differentiation. Moreover, linc-223 expression inhibits cell cycle progression and promotes monocytic differentiation of AML cells. We also demonstrate that endogenous linc-223 localizes in the cytoplasm and acts as a competing endogenous RNA for miR-125-5p, an oncogenic microRNA in leukemia. In particular, we show that linc-223 directly binds to miR-125-5p and that its knockdown increases the repressing activity of miR-125-5p resulting in the downregulation of its target interferon regulatory factor 4 (IRF4), which it was previously shown to inhibit the oncogenic activity of miR-125-5p in vivo. Furthermore, data from primary AML samples show significant downregulation of linc-223 in different AML subtypes. Therein, these findings indicate that the newly identified lncRNA linc-223 may have an important role in myeloid differentiation and leukemogenesis, at least in part, by cross-talking with IRF4 mRNA
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
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