The dark side of centromeres: types, causes and consequences of structural abnormalities implicating centromeric DNA

Centromeres are the chromosomal domains required to ensure faithful transmission of the genome during cell division. They have a central role in preventing aneuploidy, by orchestrating the assembly of several components required for chromosome separation. However, centromeres also adopt a complex structure that makes them susceptible to being sites of chromosome rearrangements. Therefore, preservation of centromere integrity is a difficult, but important task for the cell. In this review, we discuss how centromeres could potentially be a source of genome instability and how centromere aberrations and rearrangements are linked with human diseases such as cancer

Economía social y solidaria en la ciudad de Neuquén : las organizaciones y sus prácticas post-crisis del 2001

La crisis de 2001 trajo aparejada una reconfiguración social, política y económica que marcó un quiebre en la sociedad argentina. En la ciudad de Neuquén, fue el contexto de surgimiento de múltiples organizaciones que llevaron adelante prácticas asociadas a la Economía Social y Solidaria (ESS). En el presente trabajo se propone realizar una descripción de las organizaciones que tienen prácticas de Economía Social y Solidaria en la Ciudad de Neuquén, y que nacieron en el período 2001-2015. Algunos rasgos de la provincia de Neuquén y su ciudad capital se tornan fundamentales para conocer en qué marco se desenvolvió histórica y actualmente la ESS. Se realiza primero una breve descripción, de algunas características espaciales, económicas, sociales y políticas que se consideran distintivas, a modo de contextualización de la presente investigación.Fil: Fachinetti Guillén, Micaela A.. Universidad Nacional de Cuyo. Facultad de Ciencias Económicas

CENP-A Is Dispensable for Mitotic Centromere Function after Initial Centromere/Kinetochore Assembly

Human centromeres are defined by chromatin containing the histone H3 variant CENP-A assembled onto repetitive alphoid DNA sequences. By inducing rapid, complete degradation of endogenous CENP-A, we now demonstrate that once the first steps of centromere assembly have been completed in G1/S, continued CENP-A binding is not required for maintaining kinetochore attachment to centromeres or for centromere function in the next mitosis. Degradation of CENP-A prior to kinetochore assembly is found to block deposition of CENP-C and CENP-N, but not CENP-T, thereby producing defective kinetochores and failure of chromosome segregation. Without the continuing presence of CENP-A, CENP-B binding to alphoid DNA sequences becomes essential to preserve anchoring of CENP-C and the kinetochore to each centromere. Thus, there is a reciprocal interdependency of CENP-A chromatin and the underlying repetitive centromere DNA sequences bound by CENP-B in the maintenance of human chromosome segregation

Phosphorylation of CENP-A on serine 7 does not control centromere function

CENP-A is the histone H3 variant necessary to specify the location of all eukaryotic centromeres via its CENP-A targeting domain and either one of its terminal regions. In humans, several post-translational modifications occur on CENP-A, but their role in centromere function remains controversial. One of these modifications of CENP-A, phosphorylation on serine 7, has been proposed to control centromere assembly and function. Here, using gene targeting at both endogenous CENP-A alleles and gene replacement in human cells, we demonstrate that a CENP-A variant that cannot be phosphorylated at serine 7 maintains correct CENP-C recruitment, faithful chromosome segregation and long-term cell viability. Thus, we conclude that phosphorylation of CENP-A on serine 7 is dispensable to maintain correct centromere dynamics and function

ABC-IS Forest Flux Station - Report on Instrumentation, Operational Testing and First Months of Measurements

The Air and Climate Unit of the Institute for Environment and Sustainability is developing a forest flux station on the JRC Ispra site and in 2012 this project has advanced significantly. After the erection of a 36 m high self-standing tower in November 2011, the infrastructure, notably electricity, IT services and air conditioning in the adjacent container have been set up. Thereafter, the installation and testing of scientific instrumentation both on the tower and at the ground has started in view of the two projects the station participates in, i.e. the ESFRI initiative ICOS (International Carbon Observation System) and the FP7 project ECLAIRE (Effects of Climate Change on Air Pollution and Response Strategies for European Ecosystems). Measurements have started in late spring and are going on very well. The timelines of data look generally very good with few missing data points due to instrument failure or maintenance. The equipping of the station to comply with ICOS ES Level 2 requirements is proceeding well and should be finalized in 2013.JRC.H.2 - Air and Climat

Polo-like kinase 4 controls centriole duplication but does not directly regulate cytokinesis.

Centrioles organize the centrosome, and accurate control of their number is critical for the maintenance of genomic integrity. Centrioles duplicate once per cell cycle, and duplication is coordinated by Polo-like kinase 4 (Plk4). We previously demonstrated that Plk4 accumulation is autoregulated by its own kinase activity. However, loss of heterozygosity of Plk4 in mouse embryonic fibroblasts has been proposed to cause cytokinesis failure as a primary event, leading to centrosome amplification and gross chromosomal abnormalities. Using targeted gene disruption, we show that human epithelial cells with one inactivated Plk4 allele undergo neither cytokinesis failure nor increase in centrosome amplification. Plk4 is shown to localize exclusively at the centrosome, with none in the spindle midbody. Substantial depletion of Plk4 by small interfering RNA leads to loss of centrioles and subsequent spindle defects that lead to a modest increase in the rate of cytokinesis failure. Therefore, Plk4 is a centriole-localized kinase that does not directly regulate cytokinesis

Vanadium (β-(Dimethylamino)ethyl)cyclopentadienyl Complexes with Diphenylacetylene Ligands

Reduction of the V(III) (β-(dimethylamino)ethyl)cyclopentadienyl dichloride complex [η5:η1-C5H4(CH2)2NMe2]VCl2(PMe3) with 1 equiv of Na/Hg yielded the V(II) dimer {[η5:η1-C5H4(CH2)2NMe2]V(µ-Cl)}2 (2). This compound reacted with diphenylacetylene in THF to give the V(II) alkyne adduct [η5:η1-C5H4(CH2)2NMe2]VCl(η2-PhC≡CPh). Further reduction of 2 with Mg in the presence of diphenylacetylene resulted in oxidative coupling of two diphenylacetylene groups to yield the diamagnetic, formally V(V), bent metallacyclopentatriene complex [η5:η1-C5H4(CH2)2NMe2]V(C4Ph4).