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Intron splicing increases proteome complexity, promotes RNA stability, and enhances transcription. However, introns and the concomitant need for splicing extend the time required for gene expression and can cause an undesirable delay in the activation of genes. Here, we show that the plant microRNA processing factor SERRATE (SE) plays an unexpected and pivotal role in the regulation of intronless genes. Arabidopsis SE associated with more than 1000, mainly intronless, genes in a transcription-dependent manner. Chromatin-bound SE liaised with paused and elongating polymerase II complexes and promoted their association with intronless target genes. Our results indicate that stress-responsive genes contain no or few introns, which negatively affects their expression strength, but that some genes circumvent this limitation via a novel SE-dependent transcriptional activation mechanism. Transcriptome analysis of a Drosophila mutant defective in ARS2, the metazoan homologue of SE, suggests that SE/ARS2 function in regulating intronless genes might be conserved across kingdoms.

[EN] Plant survival under environmental stress requires the integration of multiple signaling pathways into a coordinated response, but the molecular mechanisms underlying this integration are poorly understood. Stress-derived energy deprivation activates the Snf1-related protein kinases1 (SnRK1s), triggering a vast transcriptional and metabolic reprogramming that restores homeostasis and promotes tolerance to adverse conditions. Here, we show that two clade A type 2C protein phosphatases (PP2Cs), established repressors of the abscisic acid (ABA) hormonal pathway, interact with the SnRK1 catalytic subunit causing its dephosphorylation and inactivation. Accordingly, SnRK1 repression is abrogated in double and quadruple pp2c knockout mutants, provoking, similarly to SnRK1 overexpression, sugar hypersensitivity during early seedling development. Reporter gene assays and SnRK1 target gene expression analyses further demonstrate that PP2C inhibition by ABA results in SnRK1 activation, promoting SnRK1 signaling during stress and once the energy deficit subsides. Consistent with this, SnRK1 and ABA induce largely overlapping transcriptional responses. Hence, the PP2C hub allows the coordinated activation of ABA and energy signaling, strengthening the stress response through the cooperation of two key and complementary pathways.

In the wake of present European interest for mapping urban noise, it seems increasingly relevant to investigate the multiple ways in which sound intersects with the everyday experiences of urban citizens. Focusing on the polluting effects of infrastructural noise, the EU-initiated project of assessment and management of environmental noise brings forth the disturbing and potentially damaging effect of environmental sound.1 But as maps of coloured streets start to circulate, and real estate prices drop in designated blue and red areas,2 it is worth remembering that sound itself is not a killer. Most of the time sound is a trivial part of everyday life involved in interactions, experiences, atmospheres, actions, etc. Although trivial, the role of the aural in the urban life world is more complex than what is suggested by sound level maps, and as such it may be a vital part of urbanity itself. The challenge for planners, designers, and architects is to deal with the auditory not only as pollution but also as an integrated part of urban experience, promoting fellowship and liveliness as well as distress., In the wake of present European interest for mapping urban noise, it seems increasingly relevant to investigate the multiple ways in which sound intersects with the everyday experiences of urban citizens. Focusing on the polluting effects of infrastructural noise, the EU-initiated project of assessment and management of environmental noise brings forth the disturbing and potentially damaging effect of environmental sound.1 But as maps of coloured streets start to circulate, and real estate prices drop in designated blue and red areas,2 it is worth remembering that sound itself is not a killer. Most of the time sound is a trivial part of everyday life involved in interactions, experiences, atmospheres, actions, etc. Although trivial, the role of the aural in the urban life world is more complex than what is suggested by sound level maps, and as such it may be a vital part of urbanity itself. The challenge for planners, designers, and architects is to deal with the auditory not only as pollution but also as an integrated part of urban experience, promoting fellowship and liveliness as well as distress.