Polycomb Regulates NF-κB Signaling in Cancer through miRNA

The mechanisms leading to the constitutive activation of NF-κB in cancers and the pathways upstream and downstream of this activation are not fully understood. In this issue of Cancer Cell, Yamagishi et al. demonstrate that Polycomb-mediated silencing of miR-31 is implicated in the aberrant activation of NF-κB signaling in tumors

Photoreceptors UVR8 and phytochrome B cooperate to optimize plant growth and defense in patchy canopies

Light is a critical source of information for plants. Plants use the phytochromes (particularly phyB) to detect light signals associated with the proximity of competitors. A low ratio of red (R) to far-red (FR) radiation (R:FR) indicates increased competition intensity, and triggers morphological responses that allow the plant to escape shading from its neighbors (the shade avoidance syndrome, SAS). Recent evidence from studies on light regulation of plant immunity has suggested that plants may also use ultraviolet-B (UV-B, 290-315 nm) radiation as an indicator of competition intensity and light availability. In addition, recent studies have shown that UV-B radiation can strongly repress SAS responses triggered by low R:FR ratios. Ambient UV-B radiation causes damaging effects on plants, such as DNA damage, and also induces adaptive photomorphogenic responses acting through a specific UV-B photoreceptor (UVR8). Therefore, the possibility exists that plants integrate information perceived by phyB and UVR8 to make decisions about growth and defense when faced with a complex light environment, such as the one that characterizes vegetation canopies. In this Letter, we address this possibility and discuss how the interplay between UV-B and R:FR signaling fine tunes plant growth and defense to optimize resource utilization in patchy canopy environments.Fil: Mazza, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Ballare, Carlos Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto de Investigaciones Biotecnológicas - Instituto Tecnológico Chascomús. Instituto de Investigaciones Biotecnológicas (sede Chascomús); Argentin

The effect of population density on shoot morphology of herbs in relation to light capture by leaves

Plants change their shapes, depending on their environment, for example, plant height increases with increasing population density. We examined the density-dependent plasticity in shoot morphology of herbs by analysing a mathematical model which identifies a number of key factors that influence shoot morphology, namely (i) solar radiation captured by leaves; (ii) shading from neighbouring plants; and (iii) utilisation efficiency of resource by leaves, stems and veins. An optimisation theory was used to obtain optimal shoot morphology in relation to maximal light capture by leaves, under trade-offs of resource partition among organs. We first evaluated the solar radiation flux per unit leaf area per day for different shoot forms. Our model predicts that the optimal internodal length of the stem that brings about the maximal light capture by leaves increases with plant population density, and this is consistent with experimental data. Moreover, our simple model can also be extended to explain the morphological plasticity in other herbs (i.e. stemless plants) that are different from our model plants with a stem. These findings illustrate how optimisation theory can be used for the analysis of plasticity in shoot morphology of plants in response to environmental changes, as well as the analysis of diversity in morphology

Photodegradation alleviates the lignin bottleneck for carbon turnover in terrestrial ecosystems

4392-4397A mechanistic understanding of the controls on carbon storage and losses is essential for our capacity to predict and mitigate human impacts on the global carbon cycle. Plant litter decomposition is an important first step for carbon and nutrient turnover, and litter inputs and losses are essential in determining soil organic matter pools and the carbon balance in terrestrial ecosystems Photodegradation, the photochemical mineralization of organic matter, has been recently identified as a mechanism for previously unexplained high rates of litter mass loss in arid lands; however, the global significance of this process as a control on carbon cycling in terrestrial ecosystems is not known. Here we show that, across a wide range of plant species, photodegradation enhanced subsequent biotic degradation of leaf litter. Moreover, we demonstrate that the mechanism for this enhancement involves increased accessibility to plant litter carbohydrates for microbial enzymes. Photodegradation of plant litter, driven by UV radiation, and especially visible (blue-green) light, reduced the structural and chemical bottleneck imposed by lignin in secondary cell walls. In leaf litter from woody species, specific interactions with UV radiation obscured facilitative effects of solar radiation on biotic decomposition. The generalized effect of sunlight exposure on subsequent microbial activity, mediated by increased accessibility to cell wall polysaccharides, suggests that photodegradation is quantitatively important in determining rates of mass loss, nutrient release, and the carbon balance in a broad range of terrestrial ecosystem

Cell heterogeneity in human breast cancer

Dos objetivos principales fueron planteados en este trabajo: 1) investigar la heterogeneidad celular en carcinomas mamarios humanos, caracterizando distintas subpoblaciones celulares respecto a proliferación y expresión de diversos marcadores tumorales; 2) obtener anticuerpos monoclonales (AMC) contra estos tumores, con propiedades citotóxicas, que reconozcan células indiferenciadas, de alto potencial proliferativo. Los estudios de heterogeneidad celular fueron realizados utilizando muestras tumorales humanas, la proliferación evaluada mediante incorporación de [3H]Timidina y marcadores por inmunohistoquímica. Los resultados permitieron establecer una secuencia de expresión de marcadores a medida que progresa la diferenciación celular y disminuye la capacidad proliferativa. Pudieron identificarse marcadores asociados a distintas etapas de la diferenciación (NCA90, receptor estroncio, receptor de progesterona, TAG72, CaMBr1, CEA) y otros que comienzan a expresarse en células indiferenciadas, altamente proliferativas, y continuarían durante todo el proceso de diferenciación (Ag2.15, PEM). Se investigaron también las propiedades del AMC FC-2.15 (anti-Ag2.15) desarrollado utilizando como inmunogeno un carcinoma mamario humano indiferenciado. FC-2.15 presento una potente citotoxicidad contra células Ag2.15+ mediando lisis por complemento humano, reconocio un antígeno presente en membrana plasmática en alta densidad (2,8x10 6 /célula) y fue lentamente internalizado. Los resultados presentados en este trabajo sugieren que FC-2.15 podría ser útil en inmunoterapia de pacientes con neoplasias Ag2.15+.The main purposes of this study were: 1) to investigate the cell heterogeneity in human breast cancer and characterize the different cell subpopulations with regard to proliferation and expression of tumor markers; 2) to obtain monoclonal antibodies (MAb) against these tumors which recognize highly undifferentiated (stem) cells, and mediate specific cytotoxicity. Cell heterogeneity was studied in human tumor samples, proliferation was evaluated by [3H]thymidine incorporation and markers by immunohistochemistry. According to the results, it could be defined a regular sequence of marker expression as cell differentiation proceeds and proliferation decreases. Some markers were identified which are expressed in different stages of the differentiation pathway (NCA90, estrogen receptor, progesterone receptor, TAG72, CaMBr1, CEA). Conversely, the expression of other markers (Ag2.15, PEM) would start in undifferentiated-highly proliferative cells and remain throughout the whole differentiation process. It was also investigated the properties of MAb FC-2.15 (anti-Ag2.15) generated using an undifferentiated human breast carcinoma as immunogen. Results showed that FC-2.15 exhibits strong human complement-mediated cytotoxicity against Ag2.15+ cells. It recognizes a high-density antigen (2.8x10 6/cell) in the cell membrane and is slowly internalized. The results obtained in this study suggest that FC-2.15 could be a useful agent for passive immuntherapy.Fil:Ballaré, Cecilia J.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

A+ Audiovisual, comunicación para todos los públicos

Trabajo Final para optar al grado académico de Licenciatura en Comunicación Social, Universidad Nacional de Córdoba (inédita) Calificación 9 (Nueve) Orientación Audiovisual¿Qué pasa con aquellas personas que no pueden comunicarse a través de los medios tradicionales? ¿ En qué parte del entramado del circuito de la comunicación se encuentran? En la actualidad, las personas con discapacidad visual y auditiva son excluidas del sistema y de los circuitos tradicionales de comunicación , encontrándose a diario con barreras que les impiden acceder a ella de forma libre. ¿A qué se debe esto? A que la información y/o los productos audiovisuales no se encuentran, en la mayoría de los casos, disponibles en formatos accesibles para todas las personas. Hoy la discapacidad no es concebida como un motivo de discriminación, creemos ser empáticos para con ella y creemos estar siendo socialmente responsables al cuidar nuestro lenguaje y formas de expresarnos. Pero cómo podríamos afirmar que no existe discriminación si la sociedad no se encuentra preparada para que todas las personas la vivan, la disfruten e intercambien opiniones, conversaciones y puntos de vista. La discriminación hacia las personas con discapacidad está ahí, es inconsciente y silenciosa...sólo que las personas no lo sabemos y no nos damos cuenta. Por eso, a partir de este momento, te invitamos a que vivas el mundo y camines a diario con la consciencia despierta, observando a tu alrededor, percibiendo todas las realidades, haciéndote preguntas, prestando atención a tus pensamientos y a las expresiones de los otros.Fil: Ballaré Scopel, Luciana. Universidad Nacional de Córdoba. Facultad de Ciencias de la Comunicación; Argentina.Fil: Carletti, Julieta. Universidad Nacional de Córdoba. Facultad de Ciencias de la Comunicación; Argentina

Remodelatge de la cromatina durant la inducció per progesterona del promotor de l'MMTV

Per a comprendre els mecanismes que governen l'expressió dels gens inclosos en els genomes eucariòtics és necessari prendre en consideració la manera en què les regions reguladores d'aquests gens estan organitzades en la cromatina. Les diferències en l'organització de la cromatina i en les modificacions químiques dels components de la cromatina expliquen els diferents patrons de l'expressió gènica en diversos tipus de cèll. ules i la seva resposta específica a senyals externs. Basant-nos en els nostres estudis sobre la inducció hormonal del promotor del mouse mammary tumour virus (MMTV), podem concloure que la seqüència nucleotídica primària determina no solament la manera en què la doble hèlix de DNA envolta l'octàmer d'histona, i així l'accessibilitat de punts d'unió per als factors de transcripció, sinó també la manera en què aquests factors estableixen sinergismes i la naturalesa del remodelatge de la cromatina dependent d'ATP. A més, la senyalització via crosstalk amb cascades de cinases citoplasmàtiques canvia l'estructura de la cromatina en els gens diana i és fonamental per a la correcta regulació a través de receptors d'hormones esteroidees.Understanding the mechanisms governing the expression of the genes encompassed in the eukaryotic genomes requires a careful consideration of the way regulatory regions of these genes are packaged in chromatin. Differences in the chromatin organization and in the chemical modifications of chromatin components account for the different patterns of gene expression in various cell types and for their specific response to external signals. Based on our studies on the hormonal induction of mouse mammary tumour virus (MMTV) promoter we conclude that the primary nucleotide sequence determines not only the way theDNAdouble helix wraps around the histone octamer, and so the accessibility of binding sites for transcription factors, but also the way these factors synergize and the nature of the ATP-dependent chromatin remodelling. Moreover, signalling via crosstalk with cytoplasmic kinase cascades changes the chromatin structure of target genes and is essential for proper regulation by steroid hormone receptors

Chromosomal loci important for cotyledon opening under UV-B in Arabidopsis thaliana

<p>Abstract</p> <p>Background</p> <p>Understanding of the genetic architecture of plant UV-B responses allows extensive targeted testing of candidate genes or regions, along with combinations of those genes, for placement in metabolic or signal transduction pathways.</p> <p>Results</p> <p>Composite interval mapping and single-marker analysis methods were used to identify significant loci for cotyledon opening under UV-B in four sets of recombinant inbred lines. In addition, loci important for canalization (stability) of cotyledon opening were detected in two mapping populations. One candidate locus contained the gene <it>HY5</it>. Mutant analysis demonstrated that HY5 was required for UV-B-specific cotyledon opening.</p> <p>Conclusions</p> <p>Structured mapping populations provide key information on the degree of complexity in the genetic control of UV-B-induced cotyledon opening in Arabidopsis. The loci identified using quantitative trait analysis methods are useful for follow-up testing of candidate genes.</p

Polycomb Factor PHF19 Controls Cell Growth and Differentiation Toward Erythroid Pathway in Chronic Myeloid Leukemia Cells

Leucèmia mieloide crònica; Diferenciació eritroïdal; PolycombLeucemia mieloide crónica; Diferenciación eritroide; PolycombChronic myeloid leukemia; Erythroid differentiation; PolycombPolycomb group (PcG) of proteins are a group of highly conserved epigenetic regulators involved in many biological functions, such as embryonic development, cell proliferation, and adult stem cell determination. PHD finger protein 19 (PHF19) is an associated factor of Polycomb repressor complex 2 (PRC2), often upregulated in human cancers. In particular, myeloid leukemia cell lines show increased levels of PHF19, yet little is known about its function. Here, we have characterized the role of PHF19 in myeloid leukemia cells. We demonstrated that PHF19 depletion decreases cell proliferation and promotes chronic myeloid leukemia (CML) differentiation. Mechanistically, we have shown how PHF19 regulates the proliferation of CML through a direct regulation of the cell cycle inhibitor p21. Furthermore, we observed that MTF2, a PHF19 homolog, partially compensates for PHF19 depletion in a subset of target genes, instructing specific erythroid differentiation. Taken together, our results show that PHF19 is a key transcriptional regulator for cell fate determination and could be a potential therapeutic target for myeloid leukemia treatment.This work was supported by the Di Croce Laboratory is supported by grants from the Spanish Ministry of Science and Innovation (BFU2016-75008-P and PID2019-108322GB-100), “Fundación Vencer El Cancer” (VEC), the European Regional Development Fund (FEDER), and from AGAUR (SGR 2017-2019). We acknowledge the support of the Spanish Ministry of Science and Innovation to the EMBL partnership, the Centro de Excelencia Severo Ochoa and the CERCA Programme/Generalitat de Catalunya. PV was supported by the Fundación Científica de la Asociación Española Contra el Cáncer. SA was funded by the Ramon y Cajal program of the Ministerio de Ciencia, Innovación y Universidades, the European Social Fund under the reference number RYC-2018-025002-I, and the Instituto de Salud Carlos III-FEDER (PI19/01814)