Changes in the cellular environment result in chromatin structure alteration, which in turn regulates gene expression. To learn about the effect of the cellular environment on the transcriptome, we studied the H3K9 demethylase KDM3A. Using RNA-seq, we found that KDM3A regulates the transcription and alternative splicing of genes associated with cell cycle and DNA damage. We showed that KDM3A undergoes phosphorylation by PKA at serine 265 following DNA damage, and that the phosphorylation is important for proper cell-cycle regulation. We demonstrated that SAT1 alternative splicing, regulated by KDM3A, plays a role in cell-cycle regulation. Furthermore we found that KDM3A's demethylase activity is not needed for SAT1 alternative splicing regulation. In addition, we identified KDM3A's protein partner ARID1A, the SWI/SNF subunit, and SRSF3 as regulators of SAT1 alternative splicing and showed that KDM3A is essential for SRSF3 binding to SAT1 pre-mRNA. These results suggest that KDM3A serves as a sensor of the environment and an adaptor for splicing factor binding. Our work reveals chromatin sensing of the environment in the regulation of alternative splicing.
TCPs are basic helix-loop-helix transcription factors. Arabidopsis (Arabidopsis thaliana) has 24 TCPs, 13 belong to Class I, and 11 to Class II (Martín-Trillo and Cubas, 2010). Class I TCPs promote, and Class II restrict, cell proliferation (Efroni et al., 2008). Previously, we showed that two Class I TCPs, TCP14 and TCP15 interact with the O-fucosyltransferase (OFT) SPINDLY (SPY) to promote cytokinin (CK) responses in young leaves and flowers (Steiner et al., 2012). SPY activity is required for TCP14 stability; the loss of SPY stimulates TCP14 proteolysis by the 26S proteasome and inhibits CK responses in flowers and leaves (Steiner et al., 2016). This is reversed by mutation in CULLIN1 (CUL1), suggesting a role for Skp, CUL1, F-box E3 ubiquitin ligase (SCF) complex in TCP14 proteolysis. OFT modify target proteins by transferring mono-fucose to serine and threonine residues (Holdener and Haltiwanger, 2019). SPY modifies the DELLA protein REPRESSOR OF ga1-3 (RGA) and increases its activity (Zentella et al., 2017). SPY also modifies PSEUDO RESPONSE REGULATOR5 (PRR5) and facilitates its proteolysis (Wang et al., 2020). Since mutation in the putative OFT catalytic domain of SPY (spy-3) is sufficient to reduce TCP14 stability, we suggested that O-fucosylation by SPY stabilizes TCP14. Here, we bring evidence that TCP14 interacts with the F-box proteins KISS ME DEADLY1 (KMD1), KMD2, and KMD4 (Kim et al., 2013) and this interaction promotes its degradation in the spy background. KMDs are negative regulators of CK signaling; they interact and destabilize the CK signaling components Type B RESPONSE REGULATOR (RR). Zhang et al. (2013) found that KMDs also target PHENYLALANINE AMMONIA LYASE (PAL) for degradation. Thus, although F-box proteins have high substrate specificity, KMDs seem to target several unrelated proteins.
Proteinase-activated receptor-1 (PAR1), triggered by thrombin and other serine proteinases such as tissue kallikrein-4 (KLK4), is a key driver of inflammation, tumor invasiveness and tumor metastasis. The PAR1 transmembrane G-protein-coupled receptor therefore represents an attractive target for therapeutic inhibitors. We thus used a computational design to develop a new PAR1 antagonist, namely, a catalytically inactive human KLK4 that acts as a proteinase substrate-capture reagent, preventing receptor cleavage (and hence activation) by binding to and occluding the extracellular R41-S42 canonical PAR1 proteolytic activation site. On the basis of in silico site-saturation mutagenesis, we then generated KLK4S207A,L185D, a first-of-a-kind 'decoy' PAR1 inhibitor, by mutating the S207A and L185D residues in wild-type KLK4, which strongly binds to PAR1. KLK4S207A,L185D markedly inhibited PAR1 cleavage, and PAR1-mediated MAPK/ERK activation as well as the migration and invasiveness of melanoma cells. This 'substrate-capturing' KLK4 variant, engineered to bind to PAR1, illustrates proof of principle for the utility of a KLK4 'proteinase substrate capture' approach to regulate proteinase-mediated PAR1 signaling.
Dominance hierarchies are ubiquitous in invertebrates and vertebrates, but little is known on how genes influence dominance rank. Our gaps in knowledge are specifically significant concerning female hierarchies, and in insects. To start filling these gaps, we studied the social bumble bee Bombus terrestris, in which social hierarchies among females are common and functionally significant. Dominance rank in this bee is influenced by multiple factors, including juvenile hormone (JH) that is a major gonadotropin in this species. We tested the hypothesis that the JH responsive transcription factor Krüppel homologue 1 (Kr-h1) mediates hormonal influences on dominance behavior. We first developed and validated a perfluorocarbon nanoparticles-based RNA interference protocol for knocking down Kr-h1 expression. We then used this procedure to show that Kr-h1 mediates the influence of JH not only on oogenesis and wax production, but also on aggression and dominance rank. To the best of our knowledge, this is the first study causally linking a gene to dominance rank in social insects, and one of only a few such studies in insects or in female hierarchies. These findings are important for determining whether there are general molecular principles governing dominance rank across gender and taxa.
In the last years, the understanding of the pathologic mechanisms of asthma and atopic dermatitis, both characterized by allergic inflammation, has greatly improved. However, it is evident that both diseases present with high heterogeneity, which complicates the diagnosis and the therapeutic approach of the patients. Moreover, some of the currently available strategies to treat asthma and atopic dermatitis are still mostly controlling the symptoms, but not to lead towards full healing, thus having these two diseases labelled as unmet clinical needs by WHO. Therefore, the "one-size-fits-all" strategy is outdated for asthma and atopic dermatitis, and there is the need of better methods to clearly diagnose the disease and tailor the therapy according to the specific symptomatology. In this regard, the use of biomarkers has been advanced in order to characterize both diseases according to their clinical signs and to facilitate the subsequent treatment. Despite the advancements made in this regard, there is still need for better and more sensitive biomarkers and for less invasive sampling methodologies, with the aim to diagnose specifically each manifestation of asthma and atopic dermatitis and to provide the best treatment with the least suffering for the patients.
It is commonly agreed that the Iron Age I–II transition was gradual and that processes of social complexity initiated in the Iron Age I simply matured in the Iron Age II. The emergence of Levantine kingdoms – whether the so-called “United Monarchy” (i.e., the highland polity) or other polities – was therefore seen as an outcome of this gradual maturation, even if the date of their emergence is hotly debated. The present paper challenges both the perceived gradual nature of Iron Age complexity and the dated understanding of state formation processes that lies behind the common scholarly reconstructions of Iron Age political developments. Instead, the paper shows that the Iron Age I–II transition was troubled and was accompanied by drastic changes in many parameters, whether settlement patterns, settlement forms, or various material traits. Acknowledging these transformations is therefore the first step in understanding the process through which local kingdoms emerged.
La Meguilat Esther (le Rouleau d’Esther) est un texte de quelques pages, dix chapitres très courts (neuf chapitres dans les Bibles chrétiennes où le dixième chapitre est inclus dans le neuvième). Sa lecture rituelle pendant la fête de Pourim (14 ou 15 Adar, selon l’endroit où elle se célèbre)1 peut prendre moins d’une demi-heure. Or, ce texte court contient des thèmes qui sont toujours d’une brûlante actualité. Le Rouleau d’Esther est un « grand miroir du monde », une œuvre qui, au-delà de l’histoire spécifique qu’elle raconte, s’ouvre vers l’universel.
