The Sharma horizon: sgraffiato wares and other glazed ceramics of the Indian Ocean trade (ca 980-1150).

International audienceSharma was one of the main ports of the Indian Ocean trade in the medieval period, a transit entrepôt connected with the networks of the Gulf merchants and dated ca 980-1150. Excavations at the site deliver a large amount of local and imported ceramic wares, from China, India, the Gulf area, Eastern Africa and Yemen itself, all dated to this limited time-span which could be named the Sharma horizon. This preliminary study of the glazed ceramics from the first seasons of excavations provides information on the exchange networks in the Indian Ocean as on the characteristics and evolution of the different pottery types at that time

Le Yémen entre Orient et Afrique : Sharma, un entrepôt du commerce médiéval sur la côte sud de l'Arabie.

International audienceDiscovered in 1996 on the coast of Hadramawt (Yemen) Sharma was a very peculiar harbour, a fortified transit entrepôt founded around 980 on the southern coast of Arabia by Gulf traders at the crossroads of their maritime networks, one of the main ports of the Indian Ocean in the 11-12th c. before it was suddenly abandoned around 1150. The paper presents the results of the first two seasons of excavations at the site, the main features of the settlement and the excavated material, a closed assemblage which brings detailed information on the ceramic productions and trade networks of this period.Découvert en 1996 sur la côte du Hadramawt au Yémen, le site de Sharma était un port tout à fait particulier, un entrepôt de transit fortifié fondé vers 980 au carrefour de leurs routes commerciales par des marchands originaires de la région du golfe Persique et qui resta l'un des ports les plus actifs de l'océan Indien jusqu'à son abandon subit vers 1150. Cet article présente les résultats des deux premières campagnes de fouilles sur le site, les principales caractéristiques de l'agglomération et du matériel mis au jour, un assemblage clos qui apporte des informations détaillées sur les productions céramiques et les réseaux d'échanges à cette époque

Ceramic production in medieval Yemen: the Yadhghat kiln site.

International audienceWhile excavating the medieval trade entrepôt of Sharma on the coast of Hadramawt (Yemen), a survey in the hinterland led to the discovery of a contemporary ceramic production centre near the village of Yadhghat in the Wâdî Jerba. The site is mostly destroyed except for a dozen small buildings and several heaps of ceramic shards associated with traces of bone-fire kilns. Excavations yielded thousands of fragments of a typical coarse ware which was found in quantity at Sharma. The site also delivered imported material typical of the Sharma horizon, c. 980-1150, but the presence of Abbasid pieces suggests that the prosperity of the kilns started before the foundation of the entrepôt, while the end of the production seems to be connected with its destruction

A MEDIEVAL TRADE ENTREPÔT AT KHOR RORI ?<br />THE STUDY OF THE ISLAMIC CERAMICS FROM AL-HAMR AL-SHARQIYA

In the course of the excavations at Khor Rori in Dhofar, ancient Sumhuram, the Italian Mission to Oman directed by A. Avanzini opened some soundings in a small site located on top of al-Hamr al-Sharqiya, a small rocky plateau at the mouth of the Wâdî Darbat, ca 500m downstream from Khor Rori. The study of the ceramics discovered in the two excavated areas indicates that this small fortified settlement was probably a medieval trading entrepôt with two different chronological phases, the first one dated to the first half or the middle of the 10th century, the second to the end of the 10th and/or the beginning of the 11th century

A role for non-coding Tsix transcription in partitioning chromatin domains within the mouse X-inactivation centre

<p>Abstract</p> <p>Background</p> <p>Delimiting distinct chromatin domains is essential for temporal and spatial regulation of gene expression. Within the X-inactivation centre region (<it>Xic</it>), the <it>Xist </it>locus, which triggers X-inactivation, is juxtaposed to a large domain of H3K27 trimethylation (H3K27me3).</p> <p>Results</p> <p>We describe here that developmentally regulated transcription of <it>Tsix</it>, a crucial non-coding antisense to <it>Xist</it>, is required to block the spreading of the H3K27me3 domain to the adjacent H3K4me2-rich <it>Xist </it>region. Analyses of a series of distinct <it>Tsix </it>mutations suggest that the underlying mechanism involves the RNA Polymerase II accumulating at the <it>Tsix </it>3'-end. Furthermore, we report additional unexpected long-range effects of <it>Tsix </it>on the distal sub-region of the <it>Xic</it>, involved in <it>Xic</it>-<it>Xic </it>trans-interactions.</p> <p>Conclusion</p> <p>These data point toward a role for transcription of non-coding RNAs as a developmental strategy for the establishment of functionally distinct domains within the mammalian genome.</p

Nuclear mRNA Degradation Pathway(s) Are Implicated in Xist Regulation and X Chromosome Inactivation

A critical step in X-chromosome inactivation (XCI), which results in the dosage compensation of X-linked gene expression in mammals, is the coating of the presumptive inactive X chromosome by the large noncoding Xist RNA, which then leads to the recruitment of other factors essential for the heterochromatinisation of the inactive X and its transcriptional silencing. In an approach aimed at identifying genes implicated in the X-inactivation process by comparative transcriptional profiling of female and male mouse gastrula, we identified the Eif1 gene involved in translation initiation and RNA degradation. We show here that female embryonic stem cell lines, silenced by RNA interference for the Eif1 gene, are unable to form Xist RNA domains upon differentiation and fail to undergo X-inactivation. To probe further an effect involving RNA degradation pathways, the inhibition by RNA interference of Rent1, a factor essential for nonsense-mediated decay and Exosc10, a specific nuclear component of the exosome, was analysed and shown to similarly impair Xist upregulation and XCI. In Eif1-, Rent1-, and Exosc10-interfered clones, Xist spliced form(s) are strongly downregulated, while the levels of unspliced form(s) of Xist and the stability of Xist RNA remain comparable to that of the control cell lines. Our data suggests a role for mRNA nuclear degradation pathways in the critical regulation of spliced Xist mRNA levels and the onset of the X-inactivation process

Highly parallel SNP genotyping reveals high-resolution landscape of mono-allelic Ube3a expression associated with locus-wide antisense transcription

We investigated the allele- and strand-specific transcriptional landscape of a megabase-wide genomic region of mouse Ube3a (ubiquitin protein ligase E3A) by means of a highly parallel SNP genotyping platform. We have successfully identified maternal-specific expression of Ube3a and its antisense counterpart (Ube3a-ATS) in brain, but not in liver. Because of the use of inter-subspecies hybrid mice, this megabase-wide analysis provided high-resolution picture of the transcriptional patterns of this region. First, we showed that brain-specific maternal expression of Ube3a is restricted to the second half part of the locus, but is absent from the first half part. Balance of allelic expression is altered in the middle of the locus. Second, we showed that expression of the brain-specific Ube3a-ATS appeared to be terminated in the region upstream to the Ube3a transcription start site. The present study highlights the importance of locus-wide competition between sense and antisense transcripts

EVOG: a database for evolutionary analysis of overlapping genes

Overlapping genes are defined as a pair of genes whose transcripts are overlapped. Recently, many cases of overlapped genes have been investigated in various eukaryotic organisms; however, their origin and transcriptional control mechanism has not yet been clearly determined. In this study, we implemented evolutionary visualizer for overlapping genes (EVOG), a Web-based DB with a novel visualization interface, to investigate the evolutionary relationship between overlapping genes. Using this technique, we collected and analyzed all overlapping genes in human, chimpanzee, orangutan, marmoset, rhesus, cow, dog, mouse, rat, chicken, Xenopus, zebrafish and Drosophila. This integrated database provides a manually curated database that displays the evolutionary features of overlapping genes. The EVOG DB components included a number of overlapping genes (10‱074 in human, 10 ‱009 in chimpanzee, 67 ‱039 in orangutan, 51 001 in marmoset, 219 in rhesus, 3627 in cow, 209 in dog, 10 ‱700 in mouse, 7987 in rat, 1439 in chicken, 597 in Xenopus, 2457 in zebrafish and 4115 in Drosophila). The EVOG database is very effective and easy to use for the analysis of the evolutionary process of overlapping genes when comparing different species. Therefore, EVOG could potentially be used as the main tool to investigate the evolution of the human genome in relation to disease by comparing the expression profiles of overlapping genes. EVOG is available at http://neobio.cs.pusan.ac.kr/evog/

The Red Sea under the Caliphal Dynasties, c. 639–1171

Students of world history will be familiar with the Red Sea as a strategic communications corridor linking the Mediterranean to the Indian Ocean. This paper examines the Red Sea region between the seventh and twelfth centuries, when it was ruled by a succession of Islamic caliphal dynasties, namely, the Umayyads, ʿAbbāsids, and Fāṭimids. It first sets out a sketch of the political history of the Red Sea and its constituent hinterland polities, including particularly Egypt, Sudan, al‐Ḥijāz, and Yemen, drawing attention to episodes and processes in which the Red Sea was significant. A section on Africa and Arabia explores the Red Sea as a zone of economic and social interaction; another section deals with the historic shift of Indian Ocean trade from the ʿAbbāsid Persian Gulf to the Fāṭimid Red Sea. Finally, the impact of the Red Sea on its constituent hinterland polities and the wider sweep of Islamic history is considered

Imprinting regulates mammalian snoRNA-encoding chromatin decondensation and neuronal nucleolar size

Imprinting, non-coding RNA and chromatin organization are modes of epigenetic regulation that modulate gene expression and are necessary for mammalian neurodevelopment. The only two known mammalian clusters of genes encoding small nucleolar RNAs (snoRNAs), SNRPN through UBE3A(15q11–q13/7qC) and GTL2(14q32.2/12qF1), are neuronally expressed, localized to imprinted loci and involved in at least five neurodevelopmental disorders. Deficiency of the paternal 15q11–q13 snoRNA HBII-85 locus is necessary to cause the neurodevelopmental disorder Prader–Willi syndrome (PWS). Here we show epigenetically regulated chromatin decondensation at snoRNA clusters in human and mouse brain. An 8-fold allele-specific decondensation of snoRNA chromatin was developmentally regulated specifically in maturing neurons, correlating with HBII-85 nucleolar accumulation and increased nucleolar size. Reciprocal mouse models revealed a genetic and epigenetic requirement of the 35 kb imprinting center (IC) at the Snrpn–Ube3a locus for transcriptionally regulated chromatin decondensation. PWS human brain and IC deletion mouse Purkinje neurons showed significantly decreased nucleolar size, demonstrating the essential role of the 15q11–q13 HBII-85 locus in neuronal nucleolar maturation. These results are relevant to understanding the molecular pathogenesis of multiple human neurodevelopmental disorders, including PWS and some causes of autism