1,721,033 research outputs found
Riflessi di numerali e di istanze di numerazione nell'italiano dell'uso contemporaneo.
No full textIl lavoro conclude un periodo di riflessione sul tema dei numerali e delle istanze di numerazione avviato nell'ambito della costituzione dell'Atlante generale dei numerali e delle istanze di numerazione, obiettivo della ricerca cofinanziata dal MIUR per il biennio 2000-2001 e svolta sotto il coordinamento di Domenico Silvestri dell'Istituto Universitario Orientale di Napoli.
Elaborato fin dall'epoca del progetto stesso, il saggio è incentrato sulla ricerca della presenza di forme implicate con i numerali nel lessico dell’italiano dell’uso contemporaneo ed è stato pensato per munire il volume di una riflessione a quella, speculare, dedicata all'incidenza della stessa categoria nell'onomastica, cui è riservata la cui altra metà del volume stesso
Characterization of the sequences encoding for Xenopus laevis box C/D snoRNP Nop56 protein
No full textNop56p was initially identified in yeast as the third common component of the ribonucleoprotein particles (snoRNPs) assembled on box C/D small nucleolar RNAs (snoRNAs). Thereafter, the characterization of Nop56p homologs in Archaea and in several eukaryotes pointed to the highly conserved structure of this factor. Studies in yeast indicate that Nop56 is not required for the stability of box C/D snoRNAs. Through the isolation of a Xenopus laevis Nop56 cDNA clone, we have been able to characterize the X laevis Nop56 protein (XNop56p). We showed that it is a common component of X laevis box C/D snoRNPs and that it displays the same electrophoretic mobility of p62 protein that we previously characterized as a box CD snoRNP component, not essential for snoRNA stability in X laevis. Mapping the 5' end of X laevis Nop56 transcript indicates that it starts with a pyrimidine tract and the analysis of genomic clones revealed a snoRNA encoded in one of NOP56 introns. Although these two characteristics could suggest that XNOP56 is a TOP gene, it is not translationally controlled in a growth-dependent manner. (C) 2002 Elsevier Science B.V. All rights reserved
RNA deregulation in Amyotrophic Lateral Sclerosis: The noncoding perspective
Full text linkRNA metabolism is central to cellular physiopathology. Almost all the molecular pathways underpinning biological processes are affected by the events governing the RNA life cycle, ranging from transcription to degradation. The deregulation of these processes contributes to the onset and progression of human diseases. In recent decades, considerable efforts have been devoted to the characterization of noncoding RNAs (ncRNAs) and to the study of their role in the homeostasis of the nervous system (NS), where they are highly enriched. Acting as major regulators of gene expression, ncRNAs orchestrate all the steps of the differentiation programs, participate in the mechanisms underlying neural functions, and are crucially implicated in the development of neuronal pathologies, among which are neurodegenerative diseases. This review aims to explore the link between ncRNA dysregulation and amyotrophic lateral sclerosis (ALS), the most frequent motoneuron (MN) disorder in adults. Notably, defective RNA metabolism is known to be largely associated with this pathology, which is often regarded as an RNA disease. We also discuss the potential role that these transcripts may play as diagnostic biomarkers and therapeutic targets
p62, a novel Xenopus laevis component of box C/D snoRNPs.
No full textU16 belongs to the family of box C/D small nucleolar RNAs (snoRNAs) whose members participate in ribosome biogenesis, mainly acting as guides for site-specific methylation of the pre-rRNA. Like all the other members of the family, U16 is associated with a set of protein factors forming a ribonucleoprotein particle, localized in the nucleolus. So far, only a few box C/D-specific proteins are known: in Xenopus laevis, fibrillarin and p68 have been identified by UV crosslinking and shown to require the conserved boxes C and D for snoRNA interaction. In this study, we have identified an additional protein factor (p62), common to box C/D snoRNPs, that crosslinks to the internal stem region, distinct from the conserved box C/D “core motif,” of U16 snoRNA. We show here that, although the absence of the core motif and, as a consequence, of fibrillarin and p68 binding prevents processing and accumulation of the snoRNA, the lack of the internal stem does not interfere with the efficient release of U16 from its host intron and only slightly affects snoRNA stability. Because this region is likely to be the binding site for p62, we propose that this protein plays an accessory role in the formation of a mature and stable U16 snoRNP particle
Nomi di attrici, ballerine e cortigiane
No full textOnomastica greca e latina di figure femminili della Roma antica
ANALYSIS OF THE MECHANISMS CONTROLLING THE EXPRESSION OF THE L1 RIBOSOMAL-PROTEIN GENE IN XENOPUS-LAEVIS
No full textA novel Mn++ dependent ribonuclease that functions in U16 snoRNA processing in X.laevis.
No full textThe intron-encoded U16 small nucleolar RNA (snoRNA) is a component of a new family of molecules which originate by processing of pre-mRNA in which they are contained. The mechanism of U16 snoRNA biosynthesis involves an initial step of endonucleolytic cleavage of the pre-mRNA with the release of a pre-snoRNA molecule; the subsequent step consists of exonucleolytic trimming that produces mature U16 molecules. In order to identify the molecular components involved in this peculiar biosynthetic pathway, we have undertaken the characterization of the endonucleolytic activity by biochemical fractionation of Xenopus laevis oocyte nuclear extract. In this paper we show the production of a protein fraction (BSF) which is highly enriched for a specific endonucleolytic activity that exactly reproduces the cleavage pattern of the U16-containing pre-mRNA identified in vivo in X. laevis oocytes and in unfractionated nuclear extract
In vitro study of processing of the intron-encoded U16 small nucleolar RNA in Xenopus laevis
No full textIt was recently shown that a new class of small nuclear RNAs is encoded in introns of protein-coding genes and that they originate by processing of the pre-mRNA in which they are contained. Little is known about the mechanism and the factors involved in this new type of processing. The L1 ribosomal protein gene of Xenopus laevis is a well-suited system for studying this phenomenon: several different introns encode for two small nucleolar RNAs (snoRNAs; U16 and U18). In this paper, we analyzed the in vitro processing of these snoRNAs and showed that both are released from the pre-mRNA by a common mechanism: endonucleolytic cleavages convert the pre-mRNA into a precursor snoRNA with 5' and 3' trailer sequences. Subsequently, trimming converts the pre-snoRNAs into mature molecules. Oocyte and HeLa nuclear extracts are able to process X. laevis and human substrates in a similar manner, indicating that the processing of this class of snoRNAs relies on a common and evolutionarily conserved mechanism. In addition, we found that the cleavage activity is strongly enhanced in the presence of Mn2+ ions
[Health education and the prevention of HIV infection in schools]
No full textThis review describes the HIV prevention strategies adopted since 1990 by the Italian Ministry of Health and Ministry of Education, coordinated by the National Health Institute, for use in Italian schools. It sets out reasons for believing that action in schools is essential in containing the spread of the HIV epidemic and presents teaching materials prepared for school use. An analysis is made of the IV national HIV information campaign, in which the Ministry of Health trained 4,000 middle and senior schools principals. The prospects for continuing the work with these 4,000 principals in the V information campaign, are also reported
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