1,117 research outputs found
The plant Arabidopsis thaliana faces the ABA-mediated processes through the DAG1, WRKY6 and WRKY18 proteins,with the control of the Polycomb Repressive Complex2.
No full textPlants, as sessile organism, have to survive to changing environmental conditions. The phytohormone abscisic acid (ABA) has a pivotal role in the adaptation to environmental challenges as well as in the regulation of plant growth and development. During maturation, dormancy and germination of seed ABA action is crucial to induce dormancy -an adaptative trait necessary to prevent early germination- and repress germination. This activity is counteracted by gibberellins (GAs), which repress dormancy while inducing germination. Therefore, the seed-to-seedling transition is mainly controlled through the ratio between ABA and GA.
In Arabidopsis thaliana, thetranscription factor Dof AFFECTING GERMINATION 1 (DAG1) controls the balance between ABA and GA to promote seed dormancy while repressing seed germination by the negative control of the ABA catabolic gene CYP707A2 and the GA biosynthetic gene GA3ox1. DAG1 not only functions during the seed-to-seedling transition, but also during seedling development, as it promotes hypocotyl elongation. RNA-seq analysis on dag1 hypocotyls proved that DAG1 is involved in the promotion of hypocotyl elongation through the control of ABA, ethylene and auxin signaling. This geneme-wide analysis revealed that seven factors belonging to the WRKY family of transcription factors, are deregulated in dag1 hypocotyls. In particular, WRKY6 and WRKY18 are involved in the ABA-mediated developmental processes and stress response. Given the close relationship between DAG1 and ABA, we have focused our study on the putative role of DAG1 in ABA-mediated stress response, and on the putative interaction between DAG1, WRKY6 and WRKY18. The results of this study revealed that DAG1 plays a role in abiotic stress response, and in particular in cold tolerance; indeed, dag1 mutant plants are significantly more tolerant to freezing temperatures respect to the wild type, suggesting that DAG1 may function as a repressor of this process. Consistently, DAG1 expression is induced by cold treatment, as well as the expression of WRKY18, which we proved is a direct target of DAG1. Interestingly, while wrky6 mutants show an increase tolerance to cold treatment respect to the wild type suggesting that the protein has a negative role in cold tolerance,wrky18 mutant plants do not show differences in the survival rate after the cold exposure respect to the wild type. Conversely the simultaneous inactivation of dag1 and wrky18 results in an increased cold tolerance, corroborating the role of DAG1 in this process.
The response to abiotic stress is mediated by a wide epigenetic transcriptomic reprogramming, which involves the POLYCOMB REPRESSIVE COMPLEX 2 (PRC2). Indeed, PRC2 is known for its key role during plant development as well as in plant response to abiotic stress. The DAG1 locus is a target of PRC2, and is marked by H3K27me3 in seeds and seedlings.. Mutations inthe catalytic subunit of PRC2 results in a severe phenotype, like embyo-lethality in plants or cancer in animals. Although theeffects of several inhibitors of the PRC2 catalytic subunit (EZH2)have long been tested in animals as a possible anti-cancer therapy, no trial with any inhibitor has ever been reported. Taking advantage of the homology of EZH2 in animals and plants, we assessed
the efficacy of a EZH2 inhibitor on Arabidopsis seeds, in order to provide a powerful tool in studying PRC2 action in plants.
We performed treatments with a compound previously reported as an EZH2 inhibitor in human leukemia cells, and we proved that is active on the Arabidopsis catalytic subunit of PRC2. Indeed, treatment with the drug reduces the total amount of H3K27me3 in a dose-dependent fashion. Consistently, the expression level of two PRC2 targets (DAG1 and WRKY70) is significantly increased following treatment with this compound. ChIP analysis confirms that enrichment of H3K27me3 on these targets significantly decreases in the presence of the inhibitor. In addition, impairment of H3K27 trimethylation in Arabidopsis seeds and seedlings affects both seed germination and root growth.
The pharmacological approach to inhibit PRC2 is efficient in plants ; therefore, this inhibitor could represent a powerful tool to further investigate the effects of the transcriptional control mediated by PRC2 in plants, also in the response to abiotic stresses
Coordination of RNA Processing Regulation by Signal Transduction Pathways
No full textSignal transduction pathways transmit the information received from external and internal cues and generate a response that allows the cell to adapt to changes in the surrounding environment. Signaling pathways trigger rapid responses by changing the activity or localization of existing molecules, as well as long-term responses that require the activation of gene expression programs. All steps involved in the regulation of gene expression, from transcription to processing and utilization of new transcripts, are modulated by multiple signal transduction pathways. This review provides a broad overview of the post-translational regulation of factors involved in RNA processing events by signal transduction pathways, with particular focus on the regulation of pre-mRNA splicing, cleavage and polyadenylation. The effects of several post-translational modifications (i.e., sumoylation, ubiquitination, methylation, acetylation and phosphorylation) on the expression, subcellular localization, stability and affinity for RNA and protein partners of many RNA-binding proteins are highlighted. Moreover, examples of how some of the most common signal transduction pathways can modulate biological processes through changes in RNA processing regulation are illustrated. Lastly, we discuss challenges and opportunities of therapeutic approaches that correct RNA processing defects and target signaling molecules
Veronica mas, Spirea, Barbarea
No full text1. Nome scientifico: Veronica chamaedrys L.
(Scrophulariaceae)
Nome attuale: Veronica comune
2. Nome scientifico: Spiraea hypericifolia L.
(Rosaceae)
Nome attuale: Spirea spagnola
3. Nome scientifico: Barbarea vulgaris r. Br.
(Brassicaceae, Cruciferae)
Nome attuale: Erba di Santa Barbar
The DOF Transcription Factors in Seed and Seedling Development
No full textThe DOF (DNA binding with one finger) family of plant-specific transcription factors (TF) was first identified in maize in 1995. Since then, DOF proteins have been shown to be present in the whole plant kingdom, including the unicellular alga Chlamydomonas reinhardtii. The DOF TF family is characterised by a highly conserved DNA binding domain (DOF domain), consisting of a CX2C-X21-CX2C motif, which is able to form a zinc finger structure. Early in the study of DOF proteins, their relevance for seed biology became clear. Indeed, the PROLAMIN BINDING FACTOR (PBF), one of the first DOF proteins characterised, controls the endosperm-specific expression of the zein genes in maize. Subsequently, several DOF proteins from both monocots and dicots have been shown to be primarily involved in seed development, dormancy and germination, as well as in seedling development and other light-mediated processes. In the last two decades, the molecular network underlying these processes have been outlined, and the main molecular players and their interactions have been identified. In this review, we will focus on the DOF TFs involved in these molecular networks, and on their interaction with other proteins
Veronica alpina (Alpine Brooklime) : Alpine Brooklime
No full textClass: Dicotyledoneae
Family: Scrophulariaceae
Genus: Veronica
Species: alpin
Veronica peregrina (Hairy Speedwell) : Hairy Speedwell
No full textClass: Dicotyledoneae
Family: Scrophulariaceae
Genus: Veronica
Species: peregrin
Ep. #024 - Veronica Strang
No full textThis recording and transcript form part of a collection of podcasts conducted by the Cultures of Energy at Rice University. Cultures of Energy brings writers, artists and scholars together to talk, think and feel their way into the Anthropocene. We cover serious issues like climate change, species extinction and energy transition. But we also try to confront seemingly huge and insurmountable problems with insight, creativity and laughter.Water, water everywhere. The human sciences have become animated by the politics, ethics and materiality of water of late and for good reason. Our guest (11:13) on this week’s Cultures of Energy podcast was one of the first to get this conversation started. Anthropologist Veronica Strang, currently Executive Director of the Institute for Advanced Study at Durham University, is the author of The Meaning of Water (Oxford, 2004) and Water: Culture and Nature (Reaktion, 2015) and a recipient of UNESCO’s International Water Prize. We talk about how the transgressive and transformative properties of water cut across cultures and how its material liquidity complicates our cultural and legal understandings of ownership and property. Veronica explains why we have to think water across scales, from its mediation of individual bodies to how its flows form communities. We talk about the infamous case of Bolivia’s water privatization, efforts to enclose water resources across the world and how contemporary politics of water are undermining democracy. Veronica also reminds us though that efforts to centralize control over water are ancient and that the movements that are now seeking to decentralize water resources also have hope. In closing we discuss cosmological and mythological water beings ranging from rainbow serpents to Chinese water dragons to the Lambton Worm, reputed to live in Durham’s own River Wear. Is our concern with hydration and floods these days informed by the moral economy and sacred vitality of water? Has urbanization caused us to lose touch with the hydrological cycle that so powerfully informed the cultural imaginations of our ancestors? Pour yourself a glass of water and listen on
DDX21 Controls Cell Cycle Progression and Autophagy in Pancreatic Cancer Cells
No full textPancreatic ductal adenocarcinoma (PDAC) is a highly aggressive disease, with a 5-year survival rate < 10%. Current therapies are poorly effective, thus urging the identification of new therapeutic approaches to face this lethal cancer. The RNA helicase DDX21 was recently shown to be upregulated and to associate with poor prognosis in PDAC. Our study shows that DDX21 is further upregulated in liver metastasis with respect to the primary PDAC lesions, and that depletion of DDX21 triggers autophagy while perturbing the cell cycle progression of PDAC. Together, our data support the oncogenic function of DDX21 in PDAC cells and uncover biological processes and pathways modulated by this RNA helicase
Lilium convallium flore pleno, Veronica minima, Liliu conualliu, Consolida media
No full text1. Nome scientifico: Convallaria majalis L. cv.
(Liliaceae)
Nome attuale: Mughetto
2. Nome scientifico: Veronica prostrata L.
(Scrophulariaceae)
Nome attuale: Veronica sdraiata
3. Nome scientifico: Convallaria majalis L.
(Liliaceae)
Nome attuale: Mughetto, Giglio delle convalli
4. Nome scientifico: Ajuga reptans L.
(Lamiacee, Labiatae)
Nome attuale: Bugula, Erba di San Lorenzo, Consolid
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