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Search Results: 1 - 10 of 194868 matches for " Barbara G. Mellone "
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A Role for the CAL1-Partner Modulo in Centromere Integrity and Accurate Chromosome Segregation in Drosophila
Chin-Chi Chen, Elizabeth Greene, Sarion R. Bowers, Barbara G. Mellone
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0045094
Abstract: The relationship between the nucleolus and the centromere, although documented, remains one of the most elusive aspects of centromere assembly and maintenance. Here we identify the nucleolar protein, Modulo, in complex with CAL1, a factor essential for the centromeric deposition of the centromere-specific histone H3 variant, CID, in Drosophila. Notably, CAL1 localizes to both centromeres and the nucleolus. Depletion of Modulo, by RNAi, results in defective recruitment of newly-synthesized CAL1 at the centromere. Furthermore, depletion of Modulo negatively affects levels of CID at the centromere and results in chromosome missegregation. Interestingly, examination of Modulo localization during mitosis reveals it localizes to the chromosome periphery but not the centromere. Combined, the data suggest that rather than a direct regulatory role at the centromere, it is the nucleolar function of modulo which is regulating the assembly of the centromere by directing the localization of CAL1. We propose that a functional link between the nucleolus and centromere assembly exists in Drosophila, which is regulated by Modulo.
Assembly of Drosophila Centromeric Chromatin Proteins during Mitosis
Barbara G. Mellone ,Kathryn J. Grive equal contributor,Vladimir Shteyn equal contributor,Sarion R. Bowers,Isaac Oderberg,Gary H. Karpen
PLOS Genetics , 2011, DOI: 10.1371/journal.pgen.1002068
Abstract: Semi-conservative segregation of nucleosomes to sister chromatids during DNA replication creates gaps that must be filled by new nucleosome assembly. We analyzed the cell-cycle timing of centromeric chromatin assembly in Drosophila, which contains the H3 variant CID (CENP-A in humans), as well as CENP-C and CAL1, which are required for CID localization. Pulse-chase experiments show that CID and CENP-C levels decrease by 50% at each cell division, as predicted for semi-conservative segregation and inheritance, whereas CAL1 displays higher turnover. Quench-chase-pulse experiments demonstrate that there is a significant lag between replication and replenishment of centromeric chromatin. Surprisingly, new CID is recruited to centromeres in metaphase, by a mechanism that does not require an intact mitotic spindle, but does require proteasome activity. Interestingly, new CAL1 is recruited to centromeres before CID in prophase. Furthermore, CAL1, but not CENP-C, is found in complex with pre-nucleosomal CID. Finally, CENP-C displays yet a different pattern of incorporation, during both interphase and mitosis. The unusual timing of CID recruitment and unique dynamics of CAL1 identify a distinct centromere assembly pathway in Drosophila and suggest that CAL1 is a key regulator of centromere propagation.
Plasticity of Fission Yeast CENP-A Chromatin Driven by Relative Levels of Histone H3 and H4
Araceli G Castillo equal contributor,Barbara G Mellone equal contributor,Janet F Partridge,William Richardson,Georgina L Hamilton,Robin C Allshire ,Alison L Pidoux
PLOS Genetics , 2007, DOI: 10.1371/journal.pgen.0030121
Abstract: The histone H3 variant CENP-A assembles into chromatin exclusively at centromeres. The process of CENP-A chromatin assembly is epigenetically regulated. Fission yeast centromeres are composed of a central kinetochore domain on which CENP-A chromatin is assembled, and this is flanked by heterochromatin. Marker genes are silenced when placed within kinetochore or heterochromatin domains. It is not known if fission yeast CENP-ACnp1 chromatin is confined to specific sequences or whether histone H3 is actively excluded. Here, we show that fission yeast CENP-ACnp1 can assemble on noncentromeric DNA when it is inserted within the central kinetochore domain, suggesting that in fission yeast CENP-ACnp1 chromatin assembly is driven by the context of a sequence rather than the underlying DNA sequence itself. Silencing in the central domain is correlated with the amount of CENP-ACnp1 associated with the marker gene and is also affected by the relative level of histone H3. Our analyses indicate that kinetochore integrity is dependent on maintaining the normal ratio of H3 and H4. Excess H3 competes with CENP-ACnp1 for assembly into central domain chromatin, resulting in less CENP-ACnp1 and other kinetochore proteins at centromeres causing defective kinetochore function, which is manifest as aberrant mitotic chromosome segregation. Alterations in the levels of H3 relative to H4 and CENP-ACnp1 influence the extent of DNA at centromeres that is packaged in CENP-ACnp1 chromatin and the composition of this chromatin. Thus, CENP-ACnp1 chromatin assembly in fission yeast exhibits plasticity with respect to the underlying sequences and is sensitive to the levels of CENP-ACnp1 and other core histones.
La ciudadanía italiana y los descendientes de ciudadanos italianos emigrados en Colombia: La eliminación de una injusticia social
Castellari,Massimiliano; Mellone,Marco;
Estudios Socio-Jurídicos , 2011,
Abstract: law is often the source of social discriminations, but, at the same time, it can be the key to delete these social discriminations. the authors try to give an example of this phenomenon, by analyzing the impact of the italian citizenship's rules over the descendants of the italian citizens emigrated abroad and, especially, in south america. indeed, according to the former italian law, only fathers could transmit iure sanguinis the citizenship to their children: moreover, women automatically lost the italian citizenship if they get a foreign citizenship by concluding a marriage with a foreign husband. these rules hardly discriminate the italian women emigrated abroad and, especially, their descendants who were prevented to get the italian's citizenship. these discriminatory rules were finally deleted by the italian constitutional court in the seventies and in the eighties: however, the effects of those rules still persisted, since the decision of the constitutional court could not overcome the temporal limit of the entry into force of the constitution (01.01.1948) and, therefore, could not "cover" the discriminatory facts occurred before that date. finally in 2009, the italian supreme court, by extending the effects ratione tempo-ris of the decisions of the constitutional court, "reopened the doors" of the italian citizenship to a huge number of italian citizenship born from italian women before the 01.01.1948. therefore, the authors focus on the social impact of this decision for all the potential italian citizens living in south america and try to assess its juridical effects over the italian law.
La ciudadanía italiana y los descendientes de ciudadanos italianos emigrados en Colombia. La eliminación de una injusticia social
Massimiliano Castellari,Marco Mellone
Estudios Socio-Jurídicos , 2011,
Abstract: El Derecho a menudo es fuente de discriminaciones sociales y a la vez puede ser la herramienta para solucionarlas. Los autores tratan de dar un ejemplo de este fenómeno, al analizar el impacto de las normas en materia de ciudadanía italiana sobre los descendientes de ciudadanositalianos emigrados al extranjero y más precisamente a América del Sur. Así, en aplicación de la vieja normativa italiana, solo el padre transmitía iure sanguinis la ciudadanía a sus descendientes: además, las mujeres perdían automáticamente la ciudadanía italiana si hubiesen adquirido una ciudadanía extranjera por matrimonio con cónyuge extranjero. Estas normas discriminaban a la mujer italiana emigrada al extranjero y especialmente a sus descendientes, quienes no podían adquirir dicha ciudadanía. Las normas discriminatorias fueron por fin abrogadas por parte de la Corte Constitucional en los a os setenta y ochenta: sin embargo, los efectos de estas seguían persistiendo, considerando que las sentencias de la Corte Constitucional no cobijaban hechos ocurridos anteriormente a la entrada en vigor de la Constitución (01.01.1948)y así no daban solución a las discriminaciones acontecidas antes de esa fecha. En el 2009, la Corte Suprema Italiana, al extender los efectos ratione temporis de lasdecisiones de la Corte Constitucional, “abría las puertas” de la ciudadanía italiana a un número considerable de ciudadanos italianos nacidos de mujeres italianas antes del 1o de enero de 1948.Así, los autores focalizan su atención sobre el impacto social de la decisión para todos los potenciales ciudadanos que viven en América del Sur y buscan evaluar sus efectos jurídicos sobre el ordenamiento italiano.
A Survey on Context-Aware Sensing for Body Sensor Networks  [PDF]
Barbara T. Korel, Simon G. M. Koo
Wireless Sensor Network (WSN) , 2010, DOI: 10.4236/wsn.2010.28069
Abstract: Context awareness in Body Sensor Networks (BSNs) has the significance of associating physiological user activity and the environment to the sensed signals of the user. The context information derived from a BSN can be used in pervasive healthcare monitoring for relating importance to events and specifically for accurate episode detection. In this paper, we address the issue of context-aware sensing in BSNs, and survey different techniques for deducing context awareness.
La arquitectura del pastoreo: Uso del espacio y sistema de asentamientos en la Puna de Atacama (Susques)
G?bel,Barbara;
Estudios atacame?os , 2002, DOI: 10.4067/S0718-10432002002300005
Abstract: this paper aims to contribute to the existing knowledge on pastoralist architecture in the andes. the regional focus of the study is put on huancar, department of susques (jujuy, argentina). we describe first the settlement structure related to the pastoralist activities of huancar; then, we present the pastoralists' spatial patterns of use. finally, we analyze the cultural meanings that space has for pastoralists.
Quelques interrogations sur la place de l’interculturel dans la formation initiale des enseignants de fran ais
Barbara G?owacka
Synergies Pologne , 2005,
Abstract:
INSTYTUCJONALIZACJA SAMORZ DU TERYTORIALNEGO A SZANSE ROZWOJU SPO ECZNO CI LOKALNYCH I REGIONALNYCH
Barbara G?ciarz
Studia Humanistyczne AGH , 2012,
Abstract:
Los estudios latinoamericanistas en Alemania
Barbara G?bel
Anuario Americanista Europeo , 2010,
Abstract: Este artículo presenta una imagen global de los estudios latinoamericanistas en Alemania, teniendo en cuenta los principales centros universitarios y no universitarios que desarrollan investigaciones sobre la región, así como la distribución de esos estudios por disciplinas y por países objeto de trabajo. Latin American Studies in Germany This article features a global picture of Latin American studies in Germany, taking into account the main universities and non-university centres where research on Latin America is carried out, as well as the distribution of those studies by discipline and by the country that is object of study.
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