2,362 research outputs found
20MO CONGRESSO NAZIONALE DELLA SOCIETÀ ITALIANA DI CRIMINOLOGIA, (GARGNANO 19-21 OTTOBRE 2006.) d) “Collaborazione tra le forze di Polizia – Unione Europea e Criminalità transnazionale” Cavalieri V.; Mastronardi V
No full textL' ospedale dei Cavalieri a Rodi
No full textAn article discussing the history and architecture of the hospital that was used by the Order of St. John in Rhodes, Greece.peer-reviewe
Localized expression of Strim1, a novel member of the TRIM-containing family, guides the skeletal morphogenetic program of the sea urchin embryo
No full textThe building of the skeleton in the indirect
developing sea urchin embryo is a complex
morphogenetic process that is executed by the
Primary Mesenchyme Cells or PMCs (Ettensohn et
al, 1997; Wilt 2002). It is well known that the
PMCs acquire most of the positional and temporal
information from the overlying ectoderm for
skeletal initiation and growth (Armstrong 1993;
Cavalieri et al, 2003; Röttinger et al, 2008). In this
study, we analyze the function of a novel gene,
encoding for a tripartite motif-containing (TRIM)
protein denoted strim1, that adds up to the list of
genes constituting the epithelial-mesenchymal
signaling network.
We show that strim1 is expressed in ectoderm
regions adjacent to the bilateral clusters of PMCs.
Strim1 misexpression causes the number of PMCs
to double and leads to skeletal abnormalities. By
micromere transplantations, we establish that
skeletal defects depend upon strim1 misexpression
in ectoderm cells. Reciprocally, knock-down of
strim1 function abrogates PMC migration and
blocks skeletogenesis. Identical phenotype is
shown by chimeras in which strim1 function is
blocked selectively in the ectoderm. We also show
that clonal expression of strim1 into ectoderm cells
from knocked-down embryos restores the correct
skeletogenic program. Finally, we report that
strim1 triggers the expression of the ectodermspecific
gene pax2/5/8, and the PMC marker sm30
(an ectoderm signaling dependent gene).
We conclude that strim1 function is able to elicit
specific gene expression both in ectoderm cells and
PMCs to guide the biomineralization during
morphogenesis.
References
Armstrong, N, Hardin, J and McClay, DR (1993). Cell-cell
interactions regulate skeleton formation in the sea urchin embryo.
Development 119, 833-40.
Cavalieri, V, Spinelli, G and Di Bernardo, M (2003). Impairing Otp
homeodomain function in oral ectoderm cells affects skeletogenesis
in sea urchin embryos. Dev Biol 262, 107-18.
Ettensohn, CA, Guss, KA, Hodor, PG, and Malinda, KM (1997).
The morphogenesis of the skeletal system of the sea urchin embryo,
in: Collier JR (Ed.), Reproductive Biology of Invertebrates, vol. VII:
Progress in Developmental Biology, Oxford & IBH publishing Co.
Pvt. Ltd. New Delhi, Calcutta. 225-265.
Röttinger, E, Saudemont, A, Duboc, V, Besnardeau, L, McClay, D
and Lepage, T (2008). FGF signals guide migration of mesenchymal
cells, control skeletal morphogenesis and regulate gastrulation
during sea urchin development. Development 135, 353-65.
Wilt, FH (2002). Biomineralization of the spicules of sea urchin
embryos. Zoolog Sci 19, 253-61
The expanding constellation of histone post-translational modifications in the epigenetic landscape
No full textThe emergence of a nucleosome-based chromatin structure accompanied the evolutionary transition from prokaryotes to eukaryotes. In this scenario, histones became the heart of the complex and precisely timed coordination between chromatin architecture and functions during adaptive responses to environmental influence by means of epigenetic mechanisms. Notably, such an epigenetic machinery involves an overwhelming number of post-translational modifications at multiple residues of core and linker histones. This review aims to comprehensively describe old and recent evidence in this exciting field of research. In particular, histone post-translational modification establishing/removal mechanisms, their genomic locations and implication in nucleosome dynamics and chromatin-based processes, as well as their harmonious combination and interdependence will be discussed
Histones, Their Variants and Post-translational Modifications in Zebrafish Development
No full textComplex multi-cellular organisms are shaped starting from a single-celled zygote, owing to elaborate developmental programs. These programs involve several layers of regulation to orchestrate the establishment of progressively diverging cell type-specific gene expression patterns. In this scenario, epigenetic modifications of chromatin are central in influencing spatiotemporal patterns of gene transcription. In fact, it is generally recognized that epigenetic changes of chromatin states impact on the accessibility of genomic DNA to regulatory proteins. Several lines of evidence highlighted that zebrafish is an excellent vertebrate model for research purposes in the field of developmental epigenetics. In this review, I focus on the dynamic roles recently emerged for histone post-translational modifications (PTMs), histone modifying enzymes, histone variants and histone themselves in the coordination between the precise execution of transcriptional programs and developmental progression in zebrafish. In particular, I first outline a synopsis of the current state of knowledge in this field during early embryogenesis. Then, I present a survey of histone-based epigenetic mechanisms occurring throughout morphogenesis, with a stronger emphasis on cardiac formation. Undoubtedly, the issues addressed in this review take on particular importance in the emerging field of comparative biology of epigenetics, as well as in translational research
Le trasformazioni urbane di Roma al tempo di Tommaso de' Cavalieri
No full textIl saggio delinea le vicende urbanistiche di Roma nel tempo in cui visse e operò Tommaso de’ Cavalieri (1509-1587), poliedrica figura di artista, sodale di Michelangelo, collezionista ed esperto stimatore, oltre che patrono ed amministratore. In particolare sono ripercorsi i principali interventi realizzati, o talvolta solo progettati, durante i pontificati di Paolo III, Giulio III, Paolo IV, Pio IV, Pio V e Gregorio XIII. Un particolare rilievo è attribuito al lungo pontificato Boncompagni (1572-1585), mettendo in evidenza alcuni interventi rimasti irrealizzati, ricostruiti sulla scorta di documentazione grafica inedita o trascurata.The essay outlines the urban history of Rome during the time in which Tommaso de’ Cavalieri lived and worked, considering the main interventions carried out, or sometimes only planned, during the pontificates of Paul III, Julius III, Paul IV, Pio V and, in particular, Gregory XIII
Identification of a putative regulator of early-histone gene expression of Paracentrotus lividus
No full textDrosophila GAGA factor (GAF) is a nuclear protein, conserved along evolution, with multiple roles in gene
regulation, chromatin remodelling, Polycomb-dependent silencing, and insulator functions (1). GAF
recognizes and specifically binds GAGAG consensus DNA motif by its C2H2-type zinc-finger domain, and
interacts with other regulatory factors by its BTB/POZ domain. We have identified plGaga, a cDNA coding
for a putative GAF of the sea urchin P. lividus, which showed significant sequence similarity with
Drosophila and vertebrate GAFs. Real time RT-PCR revealed that the plGaga RNA is always present during
embryo development decreasing rapidly in abundance at the larval pluteus stage. We raised a specific
antibody against the sea urchin GAF and used it in whole-mount immunofluorescence assays, showing that
the protein was distributed predominantly to the nuclei of the whole embryo. By Chromatin
Immunoprecipitation experiments, we showed that the sea urchin GAF not only binds the sns5 insulator,
which is essential for the regulation of the sea urchin early-histone genes (2,3), but also to other GAGA
containing sequences in the early-histone gene cluster.
1 Matharu NK et al. 2010 JMB 400 (3): 434–447
2 Melfi R et Al. 2001 JMB (1); 304:753-63
3 Cavalieri V et al. 2013 Nucleic Acids Res 37: 7407-741
“Collaborazione tra le Forze dell’Ordine (Italia-Usa)” In Atti del“Congresso Nazionale di criminologia” Gargnano 2006
No full textEpigenetic Modulation of Chromatin States and Gene Expression by G-Quadruplex Structures
No full textG-quadruplexes are four-stranded helical nucleic acid structures formed by guanine-rich sequences. A considerable number of studies have revealed that these noncanonical structural motifs are widespread throughout the genome and transcriptome of numerous organisms, including humans. In particular, G-quadruplexes occupy strategic locations in genomic DNA and both coding and noncoding RNA molecules, being involved in many essential cellular and organismal functions. In this review, we first outline the fundamental structural features of G-quadruplexes and then focus on the concept that these DNA and RNA structures convey a distinctive layer of epigenetic information that is critical for the complex regulation, either positive or negative, of biological activities in different contexts. In this framework, we summarize and discuss the proposed mechanisms underlying the functions of G-quadruplexes and their interacting factors. Furthermore, we give special emphasis to the interplay between G-quadruplex formation/disruption and other epigenetic marks, including biochemical modifications of DNA bases and histones, nucleosome positioning, and three-dimensional organization of chromatin. Finally, epigenetic roles of RNA G-quadruplexes in post-transcriptional regulation of gene expression are also discussed. Undoubtedly, the issues addressed in this review take on particular importance in the field of comparative epigenetics, as well as in translational research
Reevaluating the function of a transcription factor: MBF-1 as a sea urchin chromatin organizer ?
No full textThe Zinc-finger MBF-1 factor is involved in the expression of the early histone genes during devel-opment of the sea urchin embryo (1, 2). In spite of being a transcription activator, the DNA-binding domain of MBF-1 shares high sequence similarity with that of the chromatin organizer CTCF of vertebrates and drosophila (3). On the other hand, extensive in silico analysis failed to identify the sea urchin CTCF ortholog (4). This led us to speculate that MBF-1 somehow could have co-opted the function of CTCF during evolution of the echinoderms. Since in vertebrates CTCF binds Hox chromatin, to support our hypothesis, we first identified high-score putative binding sequences for CTCF/MBF-1 within the single sea urchin Hox gene cluster. Moreover, we observed the full evolu-tionary conservation of these binding sites in S. purpuratus and P. lividus species. Worth of men-tion, by chromatin immunoprecipitation (ChIP) assay, we detected the occupancy of MBF-1 on hox11/13-a, -b, and -c regulatory sequences at distinct stages of development. As expected from the binding of an activator, we found that the association of MBF-1 to the cis-regulatory sequences of both hox11/13-a and -b genes relates to the transcriptional status of these genes. Strikingly, we also mapped the physical binding of MBF-1 to hox11/13-c, which is instead not expressed during em-bryogenesis. Altogether, these observations indeed suggest the possibility that MBF-1, besides be-ing a transcription activator, could also function as a general chromatin organizer. To further support this hypothesis, we are planning ChIP-seq experiments to identify the association of MBF-1 to the sea urchin chromatin at a genome-wide level.
1. Di Caro, V. et al. (2007) J. Mol. Bio.,365, 1285-97.
2. Cavalieri,V et al. (2009) Nucleic Acid Res, 37,7407-7415.
3. Heger , P. et al. (2012) PNAS, 109, 17507–17512.
4. Cavalieri, V. et al. (2013) Plos Genetics, 9, e1003847
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