1,721,805 research outputs found
In margine ad IG XIV2: note su epigrafi greche di cristiani a Roma in età precostantiniana
No full textIn considering the very special attention that Denis Feissel consacred to the Greek epigraphy domain along his entire life as a scholar, the paper has the aim to take a glance about the most important dossier of Early Christian epigraphy, in Rome, assuming this specific point of view about it. The Greek (intended both as writing and as language) appears very relevant for the Early Christian communities, especially in its firts phase before Constantine. By recent data from the Epigraphic Database Bari (EDB) and by carefully chosen examples among the first inscriptions by Christians in Rome, the article has the aim to update and to collect in a hopefully coherent unitary framework some of the results of the past enquiries by the author himself in regard of the topic: firstly, about the presence of Greek itself in the dossier as a whole; but also about the peculiar ‘mixed language’ - by combining texts with Greek letters or monograms with images - and about the various phenomena of compresence and interaction of Greek and Latin (cfr. Felle 1999; Felle 2007; Felle 2018). The aimed goal is to offer a first general contribute to the study of the Early Christian inscriptions in Greek from Rome that will be included in the planned new edition of IG XIV
Due nuove iscrizioni runiche dalla catacomba romana dei Ss. Pietro e Marcellino
No full textThe aim of the paper is to publish two new inscriptions of Anglo-Saxon pilgrims (one man and a woman), discovered by the author, scratched in Runic writing (futhark) on plaster of a wall in a semi-hypogaean church in the Roman catacomb of ss. Pietro e Marcellino, along the via Labicana
DNA methylation in chromatin - complexes and mechanisms
No full textThe DNA in the eukaryotic genome is packaged into chromatin whose basic repeating unit is the nucleosome consisting of 147bp of DNA wrapped around an octameric histone core. The histone octamer is composed of two copies of each of the four histone proteins H2A, H2B, H3 and H4.
DNA methylation is an epigenetic mechanism that is involved in various important processes in the cell such as differentiation and proliferation, transcriptional regulation, genomic imprinting, X-chromosome inactivation, silencing of repetitive elements, maintenance of genomic stability and DNA repair. In the mammalian genome, DNA methylation occurs almost exclusively in the context of CpG di-nucleotides and is brought about by three DNA cytosine-5-methyltransferases that use S�adenosyl-methionine (SAM) as methyl-group donor. Due to Dnmt1�s preferential activity towards hemi-methylated DNA and the fact that it restores methylation patterns on the newly synthesized daughter strand during replication, it is referred to as the maintenance DNA methyltransferase, whereas the de novo DNA methyltransferases Dnmt3a and Dnmt3b introduce new methylation marks in the genome. Dnmt3L is structurally related but catalytically inactive and serves as a cofactor for Dnmt3a and Dnmt3b.
Importantly, DNA methylation is indispensible for mammalian embryogenesis and aberrant DNA methylation is often found concomitant with cancer. Dnmt1 was shown to be implicated in the formation of tumors, however the underlying mechanisms especially the question of Dnmt1 targeting remain largely unknown.
The goal of this thesis was to identify new Dnmt1 complexes from native tissues that would allow comparison of complex composition in tumors. ICBP90 (UHRF1) and USP7 were identified as interacting proteins from co-immunoprecipitation experiments. During the course of this study, UHRF1 was described not only to interact with Dnmt1 but to recruit Dnmt1 to replication foci during late S-phase. In vivo and in vitro immunoprecipitations revealed different possible complexes, namely Dnmt1/ICBP90, Dnmt1/USP7 and ICBP90/USP7. Furthermore, a possible trimeric complex of USP7 binding with two different domains to both Dnmt1 and ICBP90 was established. Notably, chromatin immunoprecipitation demonstrated the existence of different Dnmt1/ICBP90/USP7 complexes at four different loci in vivo, however the function in chromatin related processes awaits further investigation.
Interestingly, ICBP90 and USP7 are endowed with antagonistic enzymatic activities. ICBP90 exhibits autoubiquitinylation and ubiquitinylation activity towards histone H3, and USP7 in vitro. On the contrary, USP7 was able to target ICBP90 and histones H2A, H2B and H3 for deubiquitination in vitro whereas global levels of ubiquitinylated H2A and H2B were not changed upon knockdown or over-expression of USP7. Binding of ICBP90 and Dnmt1 to USP7 did not influence the in vitro activity of USP7. Moreover, Dnmt1 was ubiquitinylated by ICBP90 in vitro, but Dnmt1 protein or ubiquitinylation levels were not affected by USP7 over-expression or knockdown in vivo.
Future research will focus on the role of histone ubiquitinylation/deubiquitination in transcriptional repression and silencing of repetitive elements in heterochromatin.
In another project, the properties of Dnmt binding to DNA and mono-nucleosomes and the principle mechanisms of DNA methylation in chromatin by the de novo DNA methyltransferases were in focus. It could be shown that Dnmt3a and Dnmt3b2 stably associated with DNA >35bp in length, albeit longer DNA fragments were preferred indicative of a cooperative binding process. Furthermore, binding to DNA or mono-nucleosomes was highly dynamic and the interaction of mono-nucleosomes with the de novo DNA methyltransferases did not disrupt mono-nucleosomes. Dnmt3a generally bound comparably well to DNA and mono-nucleosomes with different DNA linker length whereas Dnmt3b2 preferentially bound to free DNA and mono-nucleosomes with long linker DNA.
In vitro DNA methylation assays, either performed with radioactive SAM or non-radioactive one, but following single-molecule analysis with bisulfite treatment clearly demonstrated that Dnmt3a and Dnmt3b2 could not methylate DNA within the nucleosome but only linker DNA. This indicated that the DNA strand facing opposite the histone octamer did not represent a target for methylation and that nucleosomes constitute a major restriction for DNA methylation. Further experiments will address the role of chromatin remodeling enzymes in this process.
Dnmt3L, a stimulatory factor for Dnmt3a and Dnmt3b, was shown to bind to non-methylated H3K4. Therefore, the effect of Dnmt3L on binding to DNA and nucleosomes by Dnmt3a and Dnmt3b was analyzed. Dnmt3L itself neither bound to DNA nor to mono-nucleosomes in EMSA experiments. Addition of Dnmt3L to Dnmt3a and Dnmt3b enhanced DNA binding and modified the binding behavior towards nucleosomes.
Interestingly, recombinant Dnmt3L was tightly associated with nucleosomes when purified from Sf21 insect cells. Sucrose density gradient analysis confirmed this observation as Dnmt3L was distributed over the whole gradient with nucleosomal species of different weight. However, when endogenous nucleosomes were substituted for nucleosomal templates of various sizes or �naked� DNA Dnmt3L entered the gradient by 1/3rd, although the peak fractions migrated at higher densities.
To unravel the reasons for the stable association of Dnmt3L with endogenous nucleosomes, future work will concentrate on the identification of possible loading factors, specific posttranslational histone modifications and nucleosomal architecture
New Testament quotations in some painted plaster fragments in the Israel Museum – Addenda et corrigenda to Biblia Epigraphica (nos. 162-164 and 177)
No full textScientific edition of some plaster fragments displayed in the Israel Museum in Jerusalem, bearing painted Biblical quotations, from an unknown site. The author identifies the inscribed fragments as pertaining to a fresco viewed in 1922 in the st. Theoktistos monastery in the Judaean Desert, between Jerusalem and Jericho. according to this new perspective, a different arrangement of the fragments is proposed in order to have a more correct view of the original aspect of the inscription, pertaining to the image of Christ as God painted in the main church of the monastery: the representation is a clear expression of the Orthodox faith of the monks against the growing monophysism and Christian Jacobite communities during 7th -8th centuries CE in the general context of the Muslim conquest of Middle East
Two Greek inscriptions
No full textScientific edition of the only two epigrpahs found during the very last archaeological surveys inside the complex of the Holy Sepulchre in Jerusalem. The first one is an epitaph according the current praxis of the late antique Jerusalem (the author proposes a reconstruction of the original text); the second epigraph is painted in red on a two-parts broken stone (maybe part of an architectural equipment inside the complex): it is very significant because it is an 'absolute' quotation of Gospel of Luke (Lk 23,42): καὶ ἐλεγεν τῷ Ἰησοῦ, ‘Μνήσθητί μου, Κύριε, ὅταν ἔλθῃς ἐν τῇ βασιλείᾳ σου (Lord, remember me when You come in Your kingdom)
Inscriptions, Graffiti, Graffiti devotionis causa: Some Concluding Notes and Reflections
No full textThe aim of the paper is to define what is a graffito, what is a cultic graffito and the -possible- changes of this specific idea of inscription between Antiquity, Late antiquity and Postclassical worl
Un objet privilegié d’analyse historique: la documentation épigraphique des chrétiens
No full textIl contributo presenta le sintesi di quattro conferenze tenute dall'A. per i Corsi della EPHE tra aprile e maggio 2024 su alcuni aspetti e temi della documentazione epigrafica antica di committenza cristiana (III-VII secolo)
Note e giunte alle iscrizioni cristiane di Beneventum (ICI, VIII)
No full textThe VIIIth volume of the Inscriptiones Christianae Italiae (ICI), dedicated to the Christian inscriptions of Beneventum in the
Augustan regio II (Apulia et Calabria) was published two decades ago; this paper offers an update of our knowledge of the Christian
epigraphic documents of this important city in Southern Italy from the IVth to VIth centuries (before its conquest by Lombards in
578). Six new fragments must be added to the established repertoire of the twenty-five Beneventan Christian inscriptions; in this
paper these are considered from different points of view, in direct connection with the latest archaeological acquisitions about
history and topography of Beneventum in Late Antiquity. An acclamation must be added to the documents already edited in the
VIIIth volume of ICI. The acclamation, surely Christian, is written on one of the sides of a base re-used for an honorary inscription
dedicated to a vir spectabilis, consularis Campaniae. The progressive osmosis between traditional and Christian formulas in
monumental epigraphic expression during Vth and VIth centuries is attested by an inscribed architrave (already published in ICI
VIII, but analyzed here more deeply), which might result from influences of epigraphic praxis in Byzantine Africa
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