16 research outputs found
RÎle de la dérégulation de la Lamine B1 dans l'instabilité génomique et l'inflammation : deux caractéristiques du cancer
La Lamine B1 (LMNB1) est un composant principal de la lamine nuclĂ©aire (LN), un Ă©lĂ©ment structurel principal de l'enveloppe nuclĂ©aire. La LMNB1 est impliquĂ©e dans la rĂ©gulation de nombreuses fonctions cellulaires au-delĂ de son rĂŽle structural de lâenveloppe nuclĂ©aire. La dĂ©rĂ©gulation de la Lamine B1 a Ă©tĂ© observĂ©e dans plusieurs types de tumeurs. NĂ©anmoins, aujourd'hui, les causes ou les consĂ©quences de ces altĂ©rations restent inconnues. Il est Ă noter que les cellules cancĂ©reuses ont une signature englobĂ©e dans le terme «âcaractĂ©ristiques du cancerâ». Des Ă©tudes rĂ©centes relient deux de ses caractĂ©ristiques et forces habilitantes Ă la transition du cancer : lâinstabilitĂ© du gĂ©nome et l'inflammation du microenvironnement tumoral par la prĂ©sence dans le compartiment cytoplasmique de fragments dâADN nuclĂ©aire dĂ©rivĂ© de la persistance des dommages Ă lâADN. Par la suite, ces fragments dâADN sont dĂ©tectĂ©s par des senseurs cytoplasmiques et dĂ©clenchent la rĂ©ponse immunitaire innĂ©e. Au cours de mon projet de thĂšse, je me suis intĂ©ressĂ©e Ă lâinfluence de lâaugmentation de la Lamine B1 sur la stabilitĂ© du gĂ©nome, plus prĂ©cisĂ©ment, dans l'induction du stress de rĂ©plicatif et de la voie de recombinaison homologue (RH), une voie principale de rĂ©paration des cassures a double-brin (CDB). En effet, nous montrons que les niveaux augmentĂ©s de LaminâŻB1 conduisent Ă lâaccumulation de DSB et Ă lâaugmentation des foyers de pRPA spontanĂ©s dans les cellules en phase S associĂ©s Ă lâactivation de pCHK1. De plus, lors de la surexpression de la laminB1, les cellules prĂ©sentent une sensibilitĂ© accrue Ă la camptothĂ©cine. Les cellules surexprimant la LaminâŻB1 prĂ©sentent Ă©galement une incidence Ă©levĂ©e de figures radiales lors du traitement Ă la mitomycine C couplĂ©e Ă une efficacitĂ© rĂ©duite de la rĂ©paration des cassures a double-brin par recombinaison homologue (HR). Fait intĂ©ressant, dans les cellules surexprimant la LaminâŻB1, la formation de foyers de BRCA1 et RAD51 est altĂ©rĂ©e post irradiation et lors dâun stress rĂ©plicatif induit chimiquement. De plus, nous avons obtenu des donnĂ©es prĂ©liminaires suggĂ©rant une possible signalisation dĂ©fectueuse de protĂ©ines impliquĂ©es dans la rĂ©paration des dommages Ă lâADN, expliquant la dĂ©ficience de HR observĂ©e. De plus, la LaminâŻB1 augmentĂ©e est associĂ©e Ă une sensibilitĂ© Ă une drogue utilisĂ©e dans le traitement de types spĂ©cifiques de tumeurs. Pour Ă©valuer l'impact de l'augmentation des niveaux de LaminâŻB1 dans l'induction d'une rĂ©ponse inflammatoire, nous avons Ă©tabli un modĂšle cellulaire inductibleâŻTET-LMNB1 contrĂŽlĂ© par la doxycycline. De maniĂšre remarquable, le traitement Ă la doxycycline dans les cellulesâŻTET-LMNB1 favorise l'augmentation des facteurs inflammatoires et confirme l'altĂ©ration de la RH prĂ©cĂ©demment observĂ©e. Dans l'ensemble, nos donnĂ©es mettent en Ă©vidence un nouveau rĂŽle de la LaminâŻB1. En effet, l'augmentation de cette protĂ©ine contribue Ă l'induction de l'instabilitĂ© du gĂ©nome Ă travers l'augmentation du stress rĂ©plicatif, et l'altĂ©ration de la rĂ©paration du DSB par recombinaison homologue. L'induction de facteurs inflammatoires observĂ©s, suggĂšre que la LaminâŻB1 pourrait participer Ă la relation rĂ©cemment dĂ©crite de deux caractĂ©ristiques du cancer, l'instabilitĂ© gĂ©nomique et l'inflammation.LaminâŻB1 (LMNB1) is a main element of the nuclear lamina (NL), a main structural component of the nuclear envelope. LMNB1 is involved in the regulation of many cellular functions beyond promoting structure and support to the nuclear compartment. Interestingly, LaminâŻB1 dysregulations have been reported in several types of tumors, especially an increase of lamin B1 expression. Yet, today the causes or consequences of this alterations remain elusive. Of note, cancer cells are characterized by signature features encompassed in the term hallmarks of cancer. Recent reports link two enabling forces to the cancer transition, the instability of the genome and the tumor-promoting inflammation by the presence of DNA damage-derived self-DNA in the cytoplasmic compartment. Subsequently, DNA is sensed by cytoplasmic sensors and triggers the innate immune response. During my thesis project, I focused on the influence of LaminâŻB1 increase in the stability of genome. Specifically, in the induction of replication stress and homologous recombination pathway, a main double-strand break (DSB) repair pathway. Indeed, we evidence that augmented LaminâŻB1 levels lead to the accumulation of DSBs and the augmentation of spontaneous pRPA foci in S-phase cells along with the activation of pCHK1. Additionally, upon lamin B1 overexpression, cells present an acute sensitivity to camptothecin. LaminâŻB1 overexpressing cells also display an increased incidence of radial figures upon Mitomycin C treatment coupled with a decreased efficiency of DSB repair by homologous recombination (HR). Interestingly, in cells overexpressing LaminâŻB1, BRCA1 and RAD51 foci formation was impaired upon irradiation and replication stress chemically induced. In addition, we obtained preliminary data suggesting a possible defective signaling, plausibly explaining the HR impairment observed. Moreover, augmented LaminâŻB1 associate with sensitivity to a chemical factor used in the treatment of specific types of tumors. Furthermore, to assess the impact of increasing LaminâŻB1 levels in the induction of an inflammatory response, we establish a TET-LMNB1 inducible cell model controlled by doxycycline. Remarkably, doxycycline treatment in TET-LMNB1 cells promotes the augmentation of inflammatory factors and confirms the impairment of HR previously observed. Altogether, our data highlights a new role of LaminâŻB1 overexpression in the induction of genome instability through the increase of replication stress and the impairment of DSB repair by homologous recombination. Moreover, the induction of inflammatory factors observed upon Laming B1, suggest that LaminâŻB1 might participate in the recently described crosstalk of two hallmarks of cancer, genomic instability and inflammation
Advisor competencies at the Faculty of Psychology of Pontificia Universidad Javeriana
En la presente investigaciĂłn se define el modelo de competencias del monitor acadĂ©mico de la Facultad de psicologĂa de la Pontificia Universidad Javeriana. Para ello se entrevistĂł a 11 monitores acadĂ©micos de la Facultad, con base en la entrevista de eventos crĂticos y el modelo STAR; para seleccionar los participantes se utilizĂł una convocatoria electrĂłnica y las recomendaciones de profesores de la Facultad. Adicionalmente, se contactaron 6 profesores de la Facultad para conocer las competencias que consideraban necesarias para el cargo de monitor, con las entrevistas y las respuestas de los profesores se construyĂł un inventario de 6 competencias especĂficas para el cargo del monitor: comunicaciĂłn efectiva, iniciativa, relacionamiento, organizaciĂłn del tiempo, conocimiento digital, y empatĂa; utilizada para el perfil del cargo. Con el estudio se espera fortalecer el cargo de monitor dentro de la Facultad.This investigation defines a model based on competencies for the advisor role at Pontificia Universidad Javeriana psychology faculty. For the aim of this study, 11 advisors from the Faculty were chosen to participate at competency based interview and STAR model. They were chosen through an electronic survey sent via email and by the recommendation of some teachers of the Faculty. In addition to this, 6 professors of the Faculty were contacted to know which competencies they considered necessary for an advisor to have. With the interviews made and the information received from the professors, 6 specific competencies were obtained for the role of advisor: effective communication, initiative, relationships, time organization, digital knowledge, and empathy; used for role profile. Is expected that using this research will strengthen the advisor role at the psychology faculty.PsicĂłlogo (a)Pregrad
Le vieillissement
Le vieillissement est associĂ© Ă une accumulation de cellules sĂ©nescentes produisant un environnement cellulaire inflammatoire qui pourrait expliquer diffĂ©rentes maladies liĂ©es Ă lâĂąge. Diverses situations menant Ă la sĂ©nescence sont liĂ©es Ă la prĂ©sence de dommages de lâADN. De plus, de nombreux syndromes progĂ©roĂŻdes sont associĂ©s Ă une instabilitĂ© du gĂ©nome ou de la structure nuclĂ©aire. Nous discuterons du lien Ă©troit existant entre lâaltĂ©ration des lamines, composants de lâenveloppe nuclĂ©aire, et le vieillissement cellulaire. Nous verrons que lâaltĂ©ration de lâenveloppe nuclĂ©aire, comme celle observĂ©e dans la ProgĂ©ria, est aussi associĂ©e Ă des dĂ©fauts de rĂ©paration de lâADN, Ă une persistance de dommages de lâADN et Ă un phĂ©notype inflammatoire
Increase in lamin B1 promotes telomere instability by disrupting the shelterin complex in human cells
International audienceAbstract Telomere maintenance is essential to preserve genomic stability and involves telomere-specific proteins, DNA replication and repair proteins. Lamins are key components of the nuclear envelope and play numerous roles, including maintenance of the nuclear integrity, regulation of transcription, and DNA replication. Elevated levels of lamin B1, one of the major lamins, have been observed in some human pathologies and several cancers. Yet, the effect of lamin B1 dysregulation on telomere maintenance remains unknown. Here, we unveil that lamin B1 overexpression drives telomere instability through the disruption of the shelterin complex. Indeed, lamin B1 dysregulation leads to an increase in telomere dysfunction-induced foci, telomeric fusions and telomere losses in human cells. Telomere aberrations were preceded by mislocalizations of TRF2 and its binding partner RAP1. Interestingly, we identified new interactions between lamin B1 and these shelterin proteins, which are strongly enhanced at the nuclear periphery upon lamin B1 overexpression. Importantly, chromosomal fusions induced by lamin B1 in excess were rescued by TRF2 overexpression. These data indicated that lamin B1 overexpression triggers telomere instability through a mislocalization of TRF2. Altogether our results point to lamin B1 as a new interacting partner of TRF2, that is involved in telomere stability
Estudio de ecosistemas acuĂĄticos y terrestres en el PNN el Cocuy. componentes de vegetaciĂłn y limnologĂa. cordillera oriental sector occidental
Dentro de la asignatura "EcologĂa Regional Continental" (Departamento de BiologĂa, Universidad Nacional de Colombia), se realizĂł una visita de campo al Parque Nacional Natural El Cocuy-PNN-EC (BoyacĂĄ), en septiembre de 2011. Se hicieron estudios de ambientes terrestres y acuĂĄticos desde la perspectiva de biomas, paisajes y ecosistemas. Los ecosistemas terrestres y acuĂĄticos del PNN-EC presentan como tendencia general condiciones favorables en los biomas mĂĄs superiores de superpĂĄramo y pĂĄramo, y condiciones regulares en subpĂĄramo y bosque alto andino. Los primeros se encuentran en un buen estado de conservaciĂłn, ya que exhiben las formas de vida y las especies que definen la funciĂłn ecosistĂ©mica, como es el caso de las comunidades vegetales de los pajonales y frailejonales, de las comunidades funcionales de perifiton que presentan una buena uniformidad o de los grupos de macroinvertebrados allĂ encontrados como indicadores de aguas muy limpias. A nivel general la regiĂłn comprende gran cantidad de tipos de ecosistemas. Se encontraron diferentes estructuras de comunidades en la misma franja de paisaje exhibiendo tanto diferentes caracterĂsticas fĂsico-quĂmicas de agua y suelo como diferente composiciĂłn y estructura de la comunidad. Esto refleja que la organizaciĂłn biolĂłgica de los ecosistemas depende de diversos factores que no fueron abordados en este estudio pero tambiĂ©n permite concluir que la gran diversidad que sustenta la regiĂłn se debe a la diversidad de posibilidades de mantener ecosistemas, es decir, a los diferentes ambientes en los que puede ocurrir la vida. Sin embargo, el subpĂĄramo y el bosque altoandino se encuentran en un alto grado de alteraciĂłn, tanto en el caso de los sistemas acuĂĄticos lĂłticos y lĂ©nticos, como en el de los ambientes terrestres. El clima y la geologĂa son determinante en esta regiĂłn, debido a sus caracterĂsticas de temperaturas extremas, elevada radiaciĂłn, alta humedad, vientos fuertes y agua oligotrĂłficas, todo lo cual influye sobre los organismos. Son evidentes las adaptaciones encontradas en las plantas tales como forma, tamaño y revestimiento de las hojas; en las comunidades del perifiton predominan los gĂ©neros capaces de aprovechar el nitrĂłgeno atmosfĂ©rico en ausencia nitrĂłgeno en agua; y en los macroinvertebrados son caracterĂsticos aquellos adaptados a altos niveles de oxĂgeno. En conclusiĂłn, se puede señalar que los ecosistemas terrestres se encuentran en procesos de sucesiĂłn o recuperaciĂłn mientras que los ecosistemas acuĂĄticos estĂĄn altamente conservados, por lo menos los de pĂĄramo y superpĂĄramo. Todos los ecosistemas tienden a desmejorar en la franja de menor altura (la de mayor actividad antrĂłpica), pues allĂ se encuentran organismos acuĂĄticos de grupos tolerantes y plantas en estado sucesional intermedio a inicial
Putative pathogenicity elements identified in the genome of <i>Xam</i> CIO151.
1<p>Number indicates CDS identified by key word searches in iANT.</p
Characteristics of VNTR loci for 65 <i>Xam</i> draft genome sequences.
1<p>: Repeat unit sizes are given in bp.</p>2 and 3<p>: Minimal and maximal numbers of repeats (only those in integer numbers) are given.</p>4<p>Number of samples with a complete VNTR locus in the draft genome sequence is given.</p>5<p>Number of different VNTR patterns (haplotypes) is given.</p>6<p>Hunter-Gaston discriminatory index (HGDI) scores are given.</p
Comparison of the genomic structure of <i>Xam</i> CIO151 with that of closely related members from the genus <i>Xanthomonas</i>.
<p>Scaffolds of <i>Xam</i> CIO151 were ordered based on the alignment with the complete genome sequence of <i>X. euvesicatoria</i>, <b><i>Xeu</i></b>, and then genome comparisons were performed using MUMmer (<b>A</b>). Alignment of ordered scaffolds of <i>Xam</i> CIO151 with the complete genome sequences of <i>X. axonopodis</i> pv. citri str. 306, <b><i>Xac</i></b> (<b>B</b>); <i>X. campestris</i> pv. campestris str. 8004, <b><i>Xcc</i></b> (<b>C</b>); <i>X. albilineans</i>, <b><i>Xal</i></b> (<b>D</b>); and <i>Xanthomonas oryzae</i> pv. <i>oryzae</i> PXO99<sup>A</sup>, <b><i>Xoo</i></b> (<b>E</b>) chromosomes. Scaffolds classified as parts of the chromosome of <i>Xam</i> CIO151 are shown in the y-axis. Red dots represent conserved segments while blue dots represent inverted regions.</p
Circular representation of the genome sequence of <i>Xam</i> CIO151.
<p>From outside to inside: first circle in blue indicates CDS predicted in the positive strands for the scaffolds classified as probable chromosomal regions. Second circle in red indicates the CDS predicted in the negative strand. Red spots in the black third circle indicate the region identified with atypical nucleotide composition. The fourth circle indicates the deviation pattern from the average G+C content. Inner circle shows GC skew values, positive values are shown in purple and negative values are shown in orange. Numbers correspond to scaffold IDs.</p
General features of the genome of <i>Xam</i> CIO151.
<p>General features of the genome of <i>Xam</i> CIO151.</p