Biology subjects

Gomez-Gonzalez, A.

Publications and source records attributed to Gomez-Gonzalez, A..

4 recordsLinked to original sources

bioRxiv2024

Spatiotemporal visualization of DNA replication by click chemistry reveals bubbling of viral DNA in virion formation

The organisation of human chromosomes reversibly changes in cell division, and irreversibly in apoptosis or erythropoiesis by DNA condensation and fragmentation processes. Yet, how viral replication in the nucleus affects host and viral chromatin organisation remains poorly understood. Here we used dual-color click chemistry to image human adenovirus DNA replication, demonstrating host chromatin compaction during active expansion of the viral replication compartment (VRC). Early-replicated viral DNA (vDNA) segregated from VRC and lost phospho-serine5-RNA Pol-II and viral DNA-binding protein (DBP), while late-replicated vDNA retained active RNA Pol-II, besides viral RNA-splicing and DNA-packaging proteins. Depending on replication and the assembly protein 52K, the late-stage VRCs gave rise to progeny by droplet formation of vDNA with GFP-tagged virion protein V into 52K biomolecular condensates. The study reveals distinct functions of early and late-replicated vDNA and provides insight into active and passive liquid phase separated zones conducive to selective genome packaging of nascent virions.

microbiology↗

bioRxiv2021

Arrayed multicycle drug screens identify broadly acting chemical inhibitors for repurposing against SARS CoV 2

Coronaviruses (CoVs) circulate in humans and animals, and expand their host range by zoonotic and anthroponotic transmissions. Endemic human CoVs, such as 229E and OC43 cause limited respiratory disease, and elicit short term anti-viral immunity favoring recurrent infections. Yet, severe acute respir-atory syndrome (SARS)-CoV-2 spreads across the globe with unprecedented impact on societies and economics. The world lacks broadly effective and affordable anti-viral agents to fight the pandemic and reduce the death toll. Here, we developed an image-based multicycle replication assay for focus for-mation of -coronavirus hCoV-229E-eGFP infected cells for screening with a chemical library of 5440 compounds arrayed in 384 well format. The library contained about 39% clinically used compounds, 26% in phase I, II or III clinical trials, and 34% in preclinical development. Hits were counter-selected against toxicity, and challenged with hCoV-OC43 and SARS-CoV-2 in tissue culture and human bronchial and nasal epithelial explant cultures from healthy donors. Fifty three compounds inhibited hCoV-229E-GFP, 39 of which at 50% effective concentrations (EC50) < 2M, and were at least 2-fold separated from toxicity. Thirty nine of the 53 compounds inhibited the replication of hCoV-OC43, while SARS-CoV-2 was inhibited by 11 compounds in at least two of four tested cell lines. Six of the 11 compounds are FDA-approved, one of which is used in mouth wash formulations, and five are systemic and orally available. Here, we demonstrate that methylene blue (MB) and mycophenolic acid (MPA), two broadly available low cost compounds, strongly inhibited shedding of infectious SARS-CoV-2 at the apical side of the cultures, in either pre- or post-exposure regimens, with somewhat weaker effects on viral RNA release indicated by RT-qPCR measurements. Our study illustrates the power of full cycle screens in repurposing clinical compounds against SARS-CoV-2. Importantly, both MB and MPA reportedly act as immunosuppressants, making them interesting candidates to counteract the cytokine storms affecting COVID-19 patients.

microbiology↗

bioRxiv2020

The E3 ubiquitin ligase Mind bomb 1 enhances nuclear import of viral DNA by inactivating a virion linchpin protein that suppresses exposure of virion pathogen-associated molecular patterns

In eukaryotic cells, genomes from incoming DNA viruses mount two opposing reactions, viral gene expression and innate immune response, depending on genome exposure (uncoating) to either RNA-polymerases or DNA sensors. Here we show that adenovirus particles contain a tunable linchpin protein with a dual function: response to host cues for scheduled DNA release into the nucleus, and innate immunity suppression by preventing unscheduled DNA release. Scheduled DNA release required the proteasome and ubiquitination of the viral core protein V. Cells lacking the E3 ligase Mind bomb 1 (Mib1) were resistant to wild-type adenovirus infection. Viruses lacking protein V or bearing non-ubiquitinable protein V, however, readily infected Mib1 knockout cells, yet were less infectious than wild-type virus. Their genomes were poorly imported into the nucleus and remained uncoated in the cytosol, thereby enhancing chemokine and interferon production through the DNA sensor cGAS. Our data uncover how the ubiquitin-proteasome system controls the function of a virion linchpin protein suppressing pathogen-associated molecular patterns and triggers viral DNA uncoating at the nuclear pore complex for nuclear import and infection.

microbiology↗

bioRxiv2019

Identification of 20 novel loci associated to ischemic stroke. Epigenome-Wide Association Study

RationaleDNA methylation is dynamic, varies throughout the life course, and its levels are influenced by lifestyle and environmental factors, as well as by genetic variation. The leading genetic variants at stroke risk loci identified to date explain roughly 1-2% of stroke heritability. Most of these single nucleotide polymorphisms are situated within a regulatory sequence marked by DNase I hypersensitivity sites, which would indicate involvement of an epigenetic mechanism. ObjectiveTo detect epigenetic variants associated to stroke occurrence and stroke subtypes. Methods and ResultsA two-stage case-control epigenome-wide association study was designed. The discovery sample with 401 samples included 218 ischemic stroke (IS) patients, assessed at Hospital del Mar (Barcelona, Spain) and 183 controls from the REGICOR cohort. In two independent samples (N=226 and N=166), we replicated 22 CpG sites differentially methylated in IS in 21 loci, including 2 CpGs in locus ZFHX3, which includes known genetic variants associated with stroke. The pathways associated to these loci are inflammation and angiogenesis. The meta-analysis identified 384 differentially methylated CpGs, including loci of known stroke and vascular risk genetic variants, enriched by loci involved in lipid metabolism, adipogenesis, circadian clock, and glycolysis pathways. Stratification analysis by stroke subtypes revealed distinct methylation patterns. ConclusionsWe identified a set of 22 CpGs in 21 loci associated with IS. Our analysis suggests that DNA methylation changes may contribute to orchestrating gene expression that contributes to IS.

genetics↗