A DNA break-5mC cycle activates transposable elements in Arabidopsis .

July 14, 2026| Source: Proceedings of the National Academy of Sciences of the United States of America

Plant genomic and epigenomic integrity are perpetually threatened by exogenous and endogenous DNA damage. However, the interplay between DNA damage, DNA methylation (5mC), and transposable element (TE) activity remains poorly understood. Here, we demonstrate that defective single-strand break (SSB) repair acts as a potent trigger for genome-wide TE derepression and extensive de novo DNA methylation in Arabidopsis . Mutations in ZDP/APE2, which encode conserved DNA 3'-end repair enzymes, impair the repair of 3'-blocked SSBs arising from base excision repair, ultimately leading to widespread TE activation. Concurrently, inefficient SSB repair activates the ATR-SOG1-mediated DNA damage response, which enhances the RNA-directed DNA methylation (RdDM) pathway to counteract TE activation by depositing 5mC. Paradoxically, the resulting methylation is excised by the DNA demethylase ROS1-a process that itself generates 3'-blocked SSBs requiring resolution by ZDP/APE2. In zdp ape2 mutants, ROS1-mediated 5mC excision produces additional SSBs, which in turn reactivate RdDM. This establishes a self-sustaining SSB-5mC cycle that perpetuates DNA damage and drives massive TE activation in the mutant. Our findings reveal a critical mechanistic link between SSB repair, DNA methylation dynamics, and TE derepression, positioning defective SSB repair as a major inducer of epigenomic instability.

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Nature's antivenom: Combinations of conserved rattlesnake serum metalloproteinase inhibitors block the lethal action of viper venoms.

Snakebite maims or kills several hundred thousand people each year. For more than a century, treatment has relied on antivenoms derived from animals immunized with whole venoms, but their efficacy, safety, and availability are highly variable, and it is often not well understood which specific venom components must be inhibited to prevent mortality and major morbidities. New therapeutic approaches are needed. Here, we take an evolutionary approach to antivenom design inspired by the longstanding

Physical/TechAugust 4, 2026

Abrupt transition to irreversible damage in the overdrafted Sacramento Valley aquifer system.

Groundwater extraction decreases water pressure in aquifer systems, causing reversible or irreversible deformation of the water-bearing layers that manifests as recoverable or permanent displacements of the land surface, respectively. Detecting and forecasting when and where an aquifer system transitions from a reversible, poroelastic regime, to an irreversible, inelastic regime remains a crucial challenge given the complex, heterogeneous nature of aquifer systems. Here we leverage high-resoluti

Physical/TechJuly 28, 2026

Synergistic action of different molecular mechanisms causes striking levels of insecticide resistance in the malaria vector Anopheles gambiae .

Intensifying insecticide resistance in the malaria vector Anopheles gambiae poses a serious threat to the progress achieved the last decades in reducing malaria deaths in Africa. The genetic basis of insecticide resistance is often complex, involving multiple genes and mutations. However, we still lack a clear understanding of how each mechanism contributes to overall resistance and how highly resistant phenotypes arise. In this study, we generated a suite of transgenic An. gambiae strains carry

Physical/TechJuly 28, 2026

There is no free benchmark: An institutional view of legal AI benchmarking.

Despite substantial excitement around the use of AI in law, little information exists on the performance and associated risks of the domain's widely marketed tools. Recent work, for instance, has demonstrated the significant potential for "hallucinations"-wherein models make up facts, law, and precedent-leading Chief Justice Roberts to spotlight this risk in his annual report on the judiciary. We argue that there is a need for public AI benchmarking in law. First, relative to other AI applicatio

Physical/TechJuly 28, 2026

A phosphorylation cascade involving ZmSnRK2.10-ZmRIPK2-ZmWRKY38 attenuates drought response by derepressing ZmSUS2 in maize.

Drought stress severely limits crop productivity, with transcription factors (TFs) playing pivotal roles in plant adaptation. Here, we identify the maize TF ZmWRKY38 as a positive regulator of drought tolerance. CRISPR/Cas9-mediated knockout of ZmWRKY38 increased plant sensitivity to drought compared with the wild type. We demonstrate that ZmWRKY38 binds to the promoter of the sucrose synthase gene ZmSUS2 and represses its transcription. Conversely, ZmSUS2 functions as a negative regulator of dr