16 research outputs found
The histone demethylase JMJD2A/KDM4A links ribosomal RNA transcription to nutrients and growth factors availability
The interplay between methylation and demethylation of histone lysine residues is an essential component of gene expression regulation and there is considerable interest in elucidating the roles of proteins involved. Here we report that histone demethylase KDM4A/JMJD2A, which is involved in the regulation of cell proliferation and is overexpressed in some cancers, interacts with RNA Polymerase I, associates with active ribosomal RNA genes and is required for serum-induced activation of rDNA transcription. We propose that KDM4A controls the initial stages of transition from 'poised', non-transcribed rDNA chromatin into its active form. We show that PI3K, a major signalling transducer central for cell proliferation and survival, controls cellular localization of KDM4A and consequently its association with ribosomal DNA through the SGK1 downstream kinase. We propose that the interplay between PI3K/SGK1 signalling cascade and KDM4A constitutes a mechanism by which cells adapt ribosome biogenesis level to the availability of growth factors and nutrients
Sustained virological response in HIV/HCV co-infected patients without rapid virological response (RVR) on peginterferon-ribavirin therapy
Mycorrhiza induced resistance against pests: from the lab to the field
1 página - Conferencia invitada presentada en Iberian Plant Biology 2023. XVIII Portuguese-Spanish Congress on Plant Biology and the XXV Meeting of the Spanish Society of Plant Biology. 9-12 Julio 2023, Braga, PortugalArbuscular mycorrhizal fungi (AMF) can prime plant defences increasing their resistance against
pathogens and insect herbivores. Using tomato as a model, we have shown that inoculation with
different AMF reduces the performance of the chewing herbivore Spodoptera exigua and the leaf miner
Tuta absoluta. Transcriptomic and metabolomics analyses revealed that this Mycorrhiza Induced
Resistance (MIR) is associated to boosted activation of plant direct and indirect defences in response to
the attackers. We found primed accumulation in attacked leaves of antiherbivore metabolites, including
alkaloids and polyamine conjugates, and functional analyses demonstrated that some of the identified
compounds significantly inhibit herbivore development. In addition, the symbiosis altered the volatile
blends released by the plant, and enhanced the attraction of natural enemies of the pests (Nesidiocoris
tenuis, commonly used in biocontrol programs). Finally, networks analyses allowed the identification of
key regulators of the primed response within the jasmonic acid and ethylene signalling pathways.
Despite the many studies showing induced resistance by microorganisms in different plant‐pest systems,
the variability in the protection achieved under agronomic settings is hindering the application of this
strategy in agriculture. Plant‐microbe‐herbivore interactions are highly context dependent, with multiple
biotic and abiotic factors influencing the final output. Identifying such factors is essential to optimize the
application of microbial inoculants for crop protection in agriculture. We found that the plant genotype
and nutrient availability are important drivers of the context dependency of MIR in tomato. Despite of
the variability, comparisons across different experimental scales, from controlled lab set‐ups to
commercial production conditions, confirmed that MIR can be achieved under crop production
conditions and is compatible with other biocontrol methods. Accordingly, MIR can be a relevant addition
to current Integrated Pest Management Programs