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Biology subjects

McCarthy, F.

Publications and source records attributed to McCarthy, F..

9 recordsLinked to original sources

Humans could become the greatest driver of biosphere net gain in Earth history, but we are currently the second fastest driver of biosphere loss

Human activity is transforming the shape, size, and resilience of Earths biosphere, degrading and augmenting Holocene baseline conditions at various scales, and replacing the wild biosphere with an anthropogenically modified one. We evaluate episodes of biosphere change throughout Earth history and compare them with contemporary and near-future anthropogenic changes, developing the concept of biosphere disruptors - agents that force global-scale macroevolutionary change. Transient disruptors are short-lived agents (mean 8.0x105 years), including massive volcanism and asteroid impacts. Persistent disruptors, including atmospheric and ocean oxygenation and land plant evolution, remain in the Earth System over long timescales (mean 1.6x108 years). In the geological record, transient disruptors are associated with temporary but sometimes massive biosphere degradation, whereas persistent disruptors are associated with sustained biosphere enhancement. Most anthropogenic biosphere impacts resemble those of past transient disruptors, globally degrading wild biomass and biodiversity. Humanity is driving the second highest rate of biosphere degradation in Earth history after the Cretaceous-Palaeogene bolide impact. However, humanity is the first disrupting agent capable of reflecting on and potentially transforming its impact on planetary habitability. If we can achieve this, humanity could drive the greatest rate of increase in planetary habitability in Earth history on centennial to millennial timescales.

paleontology↗

Replicating without stress: a dengue replicon model reveals distinct host rewiring to accommodate persistence

Self-replicating viral RNAs, or replicons, are widely used to study virus-host interactions and screen antiviral compounds, yet their ability to model persistent infection and host adaptation remains poorly understood. Here, we characterize a stable subgenomic dengue virus serotype 2 (DENV2) replicon (DENV2-rep) that supports long-term viral RNA replication in human hepatoma cells without triggering cytotoxicity or canonical stress responses. Compared to live DENV2 infection, which induces ER stress and global translation shutdown, DENV2-rep cells maintain active translation and polysome integrity, while mounting an antiviral transcriptional response and resisting superinfection. Transcriptomic and proteomic profiling reveals that DENV2-rep cells accommodate long-term replication by remodeling of metabolic, secretory, and cytoskeletal pathways. In contrast, acute infection uncouples transcription from protein synthesis, limiting host proteome remodeling. We also detected marked depletion of the NS5 RNA polymerase in the DENV2-rep context. Together, these findings highlight host pathways that can be rewired to support persistent RNA replication and uncover post-translational regulation of viral proteins as a potential vulnerability. Our work clarifies the strengths and limitations of replicons as models for infection and reveals how persistent vRNA replication is tolerated through selective remodeling of translation, organelle composition, and protein stability.

microbiology↗

ADAR1 Restricts Poliovirus Infection through dual disruption of translation initiation and protein coding

Viral RNAs (vRNAs) interact with hundreds of host proteins, but how these interactions shape viral infection remains largely unknown. Here we developed a mass-spectrometry approach to identify cellular RNA-binding proteins (RBPs) that enhance or inhibit infection by modulating vRNA translation. We identified 130 RBPs that associate with polysomes in human cells infected with poliovirus, including known regulators of cap-independent translation from the viral internal ribosome entry site (IRES). We find that adenosine deaminase acting on RNA (ADAR1) is recruited to polysomes during infection and edits 3 sites in the vRNA, reducing viral replication. Two edits occur in the IRES and impair internal translation initiation, while the third edit occurs in the coding region and triggers an amino acid substitution. Incorporation of this threonine-to-alanine mutation into the viral genome attenuated replication. We conclude that ADAR1 restricts poliovirus infection by both reducing vRNA translation and introducing a recurrent coding error.

cell biology↗

Spatio-temporal analysis of Vaccinia virus infection and host response dynamics using single-cell transcriptomics and proteomics

Poxviruses are a large group of DNA viruses with exclusively cytoplasmic life cycles and complex gene expression programs. A number of systems-level studies have analyzed bulk transcriptome and proteome changes upon poxvirus infection, but the cell-to-cell heterogeneity of the transcriptomic response, and the subcellular resolution of proteomic changes have remained unexplored. Here, we measured single-cell transcriptomes of Vaccinia virus-infected populations of HeLa cells and immortalized human fibroblasts, resolving the cell-to-cell heterogeneity of infection dynamics and host responses within those cell populations. We further integrated our transcriptomic data with changes in the levels and subcellular localization of the host and viral proteome throughout the course of Vaccinia virus infection. Our findings from single-cell RNA sequencing indicate conserved transcriptome changes independent of the cellular context, including widespread host shutoff, heightened expression of cellular transcripts implicated in stress responses, the rapid accumulation of viral transcripts, and the robust activation of antiviral pathways in bystander cells. While most host factors were co-regulated at the RNA and protein level, we identified a subset of factors where transcript and protein levels were discordant in infected cells; predominantly factors involved in transcriptional and post-transcriptional mRNA regulation. In addition, we detected the relocalization of several host proteins such as TENT4A, NLRC5, and TRIM5, to different cellular compartments in infected cells. Collectively, our comprehensive data provide spatial and temporal resolution of the cellular and viral transcriptomes and proteomes and offer a robust foundation for in-depth exploration of virus-host interactions in poxvirus-infected cells.

microbiology↗

Global organelle profiling reveals subcellular localization and remodeling at proteome scale

Defining the subcellular distribution of all human proteins and its remodeling across cellular states remains a central goal in cell biology. Here, we present a high-resolution strategy to map subcellular organization using organelle immuno-capture coupled to mass spectrometry. We apply this proteomics workflow to a cell-wide collection of membranous and membrane-less compartments. A graph-based representation of our data reveals the subcellular localization of over 7,600 proteins, defines spatial protein networks, and uncovers interconnections between cellular compartments. We demonstrate that our approach can be deployed to comprehensively profile proteome remodeling during cellular perturbation. By characterizing the cellular landscape following hCoV-OC43 viral infection, we discover that many proteins are regulated by changes in their spatial distribution rather than by changes in their total abundance. Our results establish that proteome-wide analysis of subcellular remodeling provides essential insights for the elucidation of cellular responses. Our dataset can be explored at organelles.czbiohub.org.

cell biology↗

mTOR controls neurotoxic lysosome exocytosis in inflammatory reactive astrocytes

Astrocytes respond and contribute to neuroinflammation by adopting inflammatory reactive states. Although recent efforts have characterized the gene expression signatures associated with these reactive states, the cell biology underlying inflammatory reactive astrocyte phenotypes remains under-explored. Here, we used CRISPR-based screening in human iPSC-derived astrocytes to identify mTOR activation a driver of cytokine-induced endolysosomal system remodeling, manifesting as alkalinization of endolysosomal compartments, decreased autophagic flux, and increased exocytosis of certain endolysosomal cargos. Through endolysosomal proteomics, we identified and focused on one such cargo - IL-32, a disease-associated pro-inflammatory cytokine not present in rodents, whose secretion mechanism is not well understood. We found that IL-32 was partially secreted in extracellular vesicles likely to be exosomes. Furthermore, we found that IL-32 was involved in the polarization of inflammatory reactive astrocyte states, was upregulated in astrocytes in multiple sclerosis lesions, and preferentially co-localized with astrocytes in hypoxic-ischemic encephalopathy. We believe that our results advance our understanding of cell biological pathways underlying inflammatory reactive astrocyte phenotypes and identify potential therapeutic targets.

cell biology↗

Workflows for rapid functional annotation of diverse arthropod genomes

Genome sequencing of a diverse array of arthropod genomes is already underway and these genomes will be used to study human health, agriculture, biodiversity and ecology. These new genomes are intended to serve as community resources and provide the foundational information that is required to apply omics technologies to a more diverse set of species. However, biologists require genome annotation to use these genomes and derive a better understanding of complex biological systems. Genome annotation incorporates two related but distinct processes: demarcating genes and other elements present in genome sequences (structural annotation); and associating function with genetic elements (functional annotation). While there are well established and freely available workflows for structural annotation of gene identification in newly assembled genomes, workflows for providing the functional annotation required to support functional genomics studies are less well understood. Genome-scale functional annotation is required for functional modeling (enrichment, networks, etc.) and a first-pass genome-wide functional annotation effort can rapidly identify under-represented gene sets for focused community annotation efforts. We present an open source, open access and containerized pipeline for genome-scale functional annotation of insect proteomes and apply it to a diverse range of arthropod species. We show that the performance of the predictions is consistent across a set of arthropod genomes with varying assembly and annotation quality.Complete instructions for running each component of the functional annotation pipeline on the command line, a high performance computing cluster and the CyVerse Discovery Environment can be found at the readthedocs site (https://agbase-docs.readthedocs.io/en/latest/agbase/workflow.html). Simple summaryGenomic technologies are accumulating information about genes at a faster rate than ever before, and sequencing initiatives like the Earth Biogenome Project, i5k and Ag100Pest are expected to increase this rate of acquisition. However, if genomic sequencing is to be used for improvement of human health, agriculture and our understanding of biological systems, it is necessary to identify genes and understand how they contribute to biological outcomes. While there are several well-established workflows for assembling genomic sequences and identifying genes, understanding gene function is essential to create actionable knowledge. Moreover this functional annotation process must be easily accessible and provide information at a genomic scale to keep up with new sequence data. We report a well defined workflow for rapid functional annotation of whole proteomes to produce Gene Ontology and pathways information. We test this workflow on a diverse set of arthropod genomes and compare it to common arthropod reference genomes. The workflow we described is freely and publicly available via a web interface on CyVerse or as biocontainers that can be deployed scalably on local computing systems.

bioinformatics↗

Crowdsourcing biocuration: the Community Assessment of Community Annotation with Ontologies (CACAO)

Experimental data about known gene functions curated from the primary literature have enormous value for research scientists in understanding biology. Using the Gene Ontology (GO), manual curation by experts has provided an important resource for studying gene function, especially within model organisms. Unprecedented expansion of the scientific literature and validation of the predicted proteins have increased both data value and the challenges of keeping pace. Capturing literature-based functional annotations is limited by the ability of biocurators to handle the massive and rapidly growing scientific literature. Within the community-oriented wiki framework for GO annotation called the Gene Ontology Normal Usage Tracking System (GONUTS), we describe an approach to expand biocuration through crowdsourcing with undergraduates. This multiplies the number of high-quality annotations in international databases, enriches our coverage of the literature on normal gene function, and pushes the field in new directions. From an intercollegiate competition judged by experienced biocurators, Community Assessment of Community Annotation with Ontologies (CACAO), we have contributed nearly 5000 literature-based annotations. Many of those annotations are to organisms not currently well-represented within GO. Over a ten-year history, our community contributors have spurred changes to the ontology not traditionally covered by professional biocurators. The CACAO principle of relying on community members to participate in and shape the future of biocuration in GO is a powerful and scalable model used to promote the scientific enterprise. It also provides undergraduate students with a unique and enriching introduction to critical reading of primary literature and acquisition of marketable skills. Significance StatementThe primary scientific literature catalogs the results from publicly funded scientific research about gene function in human-readable format. Information captured from those studies in a widely adopted, machine-readable standard format comes in the form of Gene Ontology annotations about gene functions from all domains of life. Manual annotations based on inferences directly from the scientific literature, including the evidence used to make such inferences, represents the best return on investment by improving data accessibility across the biological sciences. To supplement professional curation, our CACAO project enabled annotation of the scientific literature by community annotators, in this case undergraduates, which resulted in contribution of thousands of validated entries to public resources. These annotations are now being used by scientists worldwide.

bioinformatics↗

OpenCell: proteome-scale endogenous tagging enables the cartography of human cellular organization

Elucidating the wiring diagram of the human cell is a central goal of the post-genomic era. We combined genome engineering, confocal live-cell imaging, mass spectrometry and data science to systematically map the localization and interactions of human proteins. Our approach provides a data-driven description of the molecular and spatial networks that organize the proteome. Unsupervised clustering of these networks delineates functional communities that facilitate biological discovery, and uncovers that RNA-binding proteins form a specific sub-group defined by unique interaction and localization properties. Furthermore, we discover that remarkably precise functional information can be derived from protein localization patterns, which often contain enough information to identify molecular interactions. Paired with a fully interactive website opencell.czbiohub.org, we provide a resource for the quantitative cartography of human cellular organization.

cell biology↗