The Fgf/Erf/NCoR1/2 repressive axis controls trophoblast cell fate.

Placental development relies on coordinated cell fate decisions governed by signalling inputs. However, little is known about how signalling cues are transformed into repressive mechanisms triggering lineage-specific transcriptional signatures. Here, we demonstrate that upon inhibition of the Fgf/Erk pathway in mouse trophoblast stem cells (TSCs), the Ets2 repressor factor (Erf) interacts with the Nuclear Receptor Co-Repressor Complex 1 and 2 (NCoR1/2) and recruits it to key trophoblast genes. Genetic ablation of Erf or Tbl1x (a component of the NCoR1/2 complex) abrogates the Erf/NCoR1/2 interaction. This leads to mis-expression of Erf/NCoR1/2 target genes, resulting in a TSC differentiation defect. Mechanistically, Erf regulates expression of these genes by recruiting the NCoR1/2 complex and decommissioning their H3K27ac-dependent enhancers. Our findings uncover how the Fgf/Erf/NCoR1/2 repressive axis governs cell fate and placental development, providing a paradigm for Fgf-mediated transcriptional control.

Host-directed therapy with 2-deoxy-D-glucose inhibits human rhinoviruses, endemic coronaviruses, and SARS-CoV-2.

Rhinoviruses (RVs) and coronaviruses (CoVs) upregulate host cell metabolic pathways such as glycolysis to meet their bioenergetic demands for rapid multiplication. Using the glycolysis inhibitor 2-deoxy-d-glucose (2-DG), we assessed the dose-dependent inhibition of viral replication of minor- and major-receptor group RVs in epithelial cells. 2-DG disrupted RV infection cycle by inhibiting template negative-strand as well as genomic positive-strand RNA synthesis, resulting in less progeny virus and RV-mediated cell death. Assessment of 2-DG's intracellular kinetics revealed that after a short-exposure to 2-DG, the active intermediate, 2-DG6P, is stored intracellularly for several hours. Finally, we confirmed the antiviral effect of 2-DG on pandemic SARS-CoV-2 and showed for the first time that it also reduces replication of endemic human coronaviruses. These results provide further evidence that 2-DG could be used as a broad-spectrum antiviral.

Long-Term Confocal Imaging of Arabidopsis thaliana Roots for Simultaneous Quantification of Root Growth and Fluorescent Signals.

Observing cellular and molecular processes in living organisms is key for understanding many important biological processes. Confocal microscopy is excellently suited for this as it enables the observation of molecules and cells in tissue layers of living organisms in three dimensions over time. However, in continuously growing organs, such as plant roots, observations over extended time spans become difficult as the specimen quickly grows out the field of view. Here, we provide a protocol that allows for the acquisition of confocal microscope time-lapse images of root tips spanning many hours, as the growing root tip is tracked and the microscopy is automatized to change the position of the stage. Importantly, due to its specific setup, this protocol allows for observing the effects of chemical stimuli or for creating specific growth conditions by precisely defining the growth medium during imaging. The protocol is suitable for observing multiple fluorophores, thereby moving beyond the level of individual genes. It is also simple enough to conduct larger numbers of these assays. Here we exemplify our method by describing the observation of root growth and GFP intensity in root tips under iron depletion conditions.