Cell genomics最新文献

It remains unknown whether early embryonic cells harbor a blueprint for future enhancers that regulate the expression of lineage-specific genes in adult tissues. Here, we demonstrate that embryonic stem cells (ESCs) have transcriptionally competent chromatin regions (CCRs) prepared to induce the expression of lineage genes prior to differentiation. CCRs represent activatable pre-enhancers within the topological chromatin domains of lineage genes, marked by chromatin signatures distinguishable from primed/poised enhancers, enabling their genome-wide identification. The pioneer transcription factor (TF) FOXA2 preferentially binds CCRs during early lineage specification, promoting their conversion into active enhancers. CCRs can be harnessed to boost the expression of master TFs and promote the direct reprogramming of ESCs into differentiated cells, showcasing their potential for practical applications. Our findings identify a mechanism by which ESCs rapidly establish enhancer activity during early lineage differentiation and expand our understanding of the epigenetic features supporting transcriptional regulation and cellular plasticity.

In this meet-the-author Q&A, Scientific Editor Sara Rohban and Editor-in-Chief Laura Zahn speak with Junyue Cao about his Cell Genomics paper. He discusses his ambitions to study aging and how his newly developed method, EnrichSci, was used to look at changes over time in oligodendrocytes in the brain.

Red blood cells (RBCs) transport oxygen but accumulate oxidative damage over time, reducing function in vivo and during storage, critical for transfusions. To explore the genetics of RBC resilience, we profiled proteins, metabolites, and lipids from fresh and stored RBCs from 350 genetically diverse mice. Our analysis identified over 6,000 quantitative trait loci (QTLs). Compared to other tissues, the prevalence of trans genetic effects over cis ones reflects the absence of de novo protein synthesis in anucleated RBCs. QTL hotspots at Hbb, Hba, Mon1a, and (storage-specific) Steap3 linked ferroptosis to hemolysis. Proteasome QTLs clustered at multiple loci, underscoring the importance of degrading oxidized proteins. Post-translational modification (PTM) QTLs mapped predominantly to hemoglobins, including cysteine residues. The loss of reactive C93 in humanized mice (hemoglobulin beta [HBB] C93A) disrupted redox balance, glutathione pools, glutathionylation, and redox PTMs. These findings highlight genetic regulation of RBC oxidation, with implications for transfusion biology and oxidative-stress-dependent hemolytic disorders.

Polygenic scores (PGSs) that can predict response to interventions can facilitate precision medicine and are detectable in observational datasets as PGS-by-exposure (PGS×E) interactions. PGSs based on interactions (iPGSs) or variance effects (vPGSs) may be more powerful than standard PGSs for detecting PGS×E, but these have yet to be systematically compared. We describe a generalized pipeline for developing and comparing these PGS types and apply it to detect genetic modification of the relationship between adiposity (measured by BMI) and a broad set of cardiometabolic risk factors. Our applied analysis in the UK Biobank identified significant PGS×BMI for 16/20 risk factors, most consistently for the iPGS approach. Many interactions replicated in All of Us (AoU); for example, we observed a 72% larger BMI-alanine aminotransferase association in the top iPGS decile in AoU. Our study provides a framework for the comparison of PGS×E strategies and informs efforts toward clinically useful response-focused PGSs.

The study of early evolutionary history provides an account of how the foundational features of life as we know it first emerged. Phylogenetic analysis is a powerful method in the study of early evolution because it uses molecular evidence that has been inherited from the ancient organisms themselves. Here, we describe an important yet understudied type of protein family, universal paralogs, that retain phylogenetic signals from evolutionary events predating the last universal common ancestor of life, offering a unique window into early evolution. We survey recent advances in the study of universal paralogs and discuss how emerging computational tools enhance our ability to use these protein families to describe the very earliest stages of evolution with increasing detail and accuracy. Such research will greatly improve our understanding of how life emerged and subsequently evolved on the ancient Earth.

In this issue of Cell Genomics, Tortora and Fudenberg develop a first-principles framework in which loop extrusion is quantitatively regulated by multiple cohesin-associated factors, giving rise to "bursty extrusion." This model predicts regulator-dependent changes in motor kinetics, chromatin contact patterns, and chromosome-scale morphology across spatial scales, providing a mechanistically grounded basis for quantitative modeling of 3D genome architecture.

Cohesin drives genome organization via loop extrusion, orchestrated by the dynamic exchange of multiple essential accessory proteins. Although these regulators bind the core cohesin complex only transiently, their disruption can dramatically alter loop-extrusion dynamics and chromosome morphology. Still, a quantitative theory of cohesin regulation and its interplay with genome folding is still elusive. Here, we derive a chemical-reaction network model of loop-extrusion regulation from first principles that is fully specified by available in vivo measurements. This "bursty extrusion model" untangles the distinct roles of regulators, whose exchange coincides with intermittent periods of motor activity. By incorporating bursty extrusion in polymer simulations, we reveal how variations in regulatory protein abundance can alter chromatin architecture across length and timescales. Our results are corroborated by in vivo and in vitro observations, bridging the gap between cohesin-regulator dynamics at the molecular scale and their genome-wide consequences on chromosome organization.

Cell-free DNA (cfDNA) end motifs serve as fragmentomics biomarkers for cancer. Prior studies primarily focused on 5' ends, whereas 3' ends were overlooked due to artifactual modification in existing sequencing protocols. We utilized single-stranded library preparation ("2-end sequencing") to assess the native 5' and 3' end motifs (EM5 and EM3, respectively). Additionally, we demonstrated diagnostic power from the nucleotide motifs located immediately upstream and downstream of 5' and 3' ends, named pre-end motifs (PREMs) and post-end motifs (POEMs). These fragmentomics markers collectively achieved an area under the curve (AUC) of 0.95 for hepatocellular carcinoma (HCC) detection. Fragmentomics-based methylation analysis of 3' ends (3' FRAGMA) improved detection of HCC (AUC: 0.97). We further developed "4-end sequencing" to interrogate both ends of both strands of a double-stranded cfDNA molecule, enhancing fragmentomics-based cancer detection. Holistic end profiling adds to the armamentarium of liquid biopsy and sheds light on the biology of cfDNA fragmentation.

Interstitial lung diseases (ILD) are characterized by fibrotic scarring of the lung parenchyma with remarkably unfavorable prognosis. Using single-nucleus RNA sequencing and spatial transcriptomics, we generated a comprehensive cellular network of the distal lung and its alterations in fibrosis. Integration with histopathology revealed that the transformation of normal parenchyma into fibrotic tissue is accompanied by ectopic bronchiolization and decellularization. Areas of active fibrosis were characterized by co-localization of pro-fibrotic CTHRC1-hi fibroblasts and aberrant transitional epithelial cells. We modeled this maladaptive differentiation of alveolar epithelial cells using organoids, demonstrating that all three pro-inflammatory ligands present in this pathogenic niche, TGF-β, IL-1β, and TNF-α, are jointly required for their induction. Additionally, we identified a requirement for the transcription factor NFATC4 during myofibroblast differentiation driven by soluble factors or mechanosensing. Collectively, this work identifies essential molecular drivers of the cellular interactions underlying lung fibrosis.

Gene expression shapes the nervous system at every biological level, from molecular and cellular processes defining neuronal identity and function to systems-level wiring and circuit dynamics underlying behavior. Here, we generate the first high-resolution, single-cell transcriptomic atlas of the adult Drosophila melanogaster central brain by integrating multiple datasets, achieving an unprecedented 10-fold coverage of every neuron in this complex tissue. We show that a neuron's genetic identity overwhelmingly reflects its developmental origin, preserving a genetic address based on both lineage and birth order. We reveal foundational rules linking neurogenesis to transcriptional identity and provide a framework for systematically defining neuronal types. This atlas provides a powerful resource for mapping the cellular substrates of behavior by integrating annotations of hemilineage, cell types/subtypes, and molecular signatures of underlying physiological properties. It lays the groundwork for a long-sought bridge between developmental processes and the functional circuits that give rise to behavior.