Cell genomics最新文献

Most genetic loci linked to polygenic traits are in non-coding regions, with complex regulation and linkage disequilibrium (LD), complicating causal variant and gene prioritization. We used multiplexed single-cell CRISPR interference and activation perturbations to investigate cis-regulatory element (CRE) and gene expression relationships within tight LD in the endogenous chromatin context. We demonstrated the prevalence of multiple causality in perfect LD (pLD) for independent expression quantitative trait loci (eQTLs) and uncovered fine-grained genetic effects on gene expression within pLD, which are difficult to decipher using traditional eQTL fine-mapping or existing computational methods. We found that over one-third of the causal CREs lack classical epigenetic markers prior to perturbation, and we functionally validated one of these hidden regulatory mechanisms. Leveraging Multiome single-cell epigenetic and sequence perturbations, we highlighted the regulatory plasticity of the human genome. Our study will guide the exploration of missing causal mechanisms underlying molecular trait regulation and disease development.

3D chromatin structure is critical for the regulation of gene expression during development. Here we used Micro-C assays at 100-bp resolution to map genome organization in Drosophila melanogaster throughout the first half of embryogenesis. These high-resolution contact maps reveal fine-scale features such as loops and boundaries delineating topologically associating domains. Notably, we observe that 3D chromatin structures form prior to zygotic genome activation and persist during successive mitotic cycles. Integrative analysis with 149 public chromatin immunoprecipitation sequencing (ChIP-seq) datasets identifies four classes of chromatin structuring elements, including a distinct group enriched for GAGA-associated factor (GAF) and Zelda binding, associated with developmental-gene regulation. These elements are mitotically retained and exhibit sequence and structure similarity between D. melanogaster and D. virilis. We propose that 3D chromatin organization in the pre-cellular embryo facilitates deployment of developmentally regulated genes during Drosophila embryogenesis.

Neuropsychiatric disorders lack effective treatments due to a limited understanding of the underlying cellular and molecular mechanisms. To address this, we integrated population-scale single-cell genomics data and analyzed 23 cell-type-level gene regulatory networks across schizophrenia, bipolar disorder, and autism. Our analysis revealed potential druggable transcription factors co-regulating known risk genes that converge into cell-type-specific co-regulated modules. We applied graph neural networks on those modules to prioritize novel risk genes and leveraged them in a network-based drug repurposing framework to identify 220 drug molecules with the potential for targeting specific cell types. We found evidence for 37 of these drugs in reversing disorder-associated transcriptional phenotypes. Additionally, we discovered 335 drug-cell quantitative trait loci (eQTLs), revealing genetic variation's influence on drug target expression at the cell-type level. Our results provide a single-cell network medicine resource that provides potential mechanistic insights for advancing treatment options for neuropsychiatric disorders.

Human gut microbiota produces unmodified bacteriocins, natural antimicrobial peptides that protect against pathogens and regulate host physiology. However, current bioinformatic tools limit the comprehensive investigation of bacteriocins' biosynthesis, obstructing research into their biological functions. Here, we introduce IIBacFinder, a superior analysis pipeline for identifying unmodified class II bacteriocins. Through large-scale bioinformatic analysis and experimental validation, we demonstrate their widespread distribution across the bacterial kingdom, with most being habitat specific. Analyzing over 280,000 bacterial genomes, we reveal the diverse potential of human gut bacteria to produce these bacteriocins. Guided by meta-omics analysis, we synthesized 26 hypothetical bacteriocins from gut commensal species, with 16 showing antibacterial activities. Further ex vivo tests show minimal impact of narrow-spectrum bacteriocins on human fecal microbiota. Our study highlights the huge biosynthetic potential of unmodified bacteriocins in the human gut, paving the way for understanding their biological functions and health implications.

The spatial organization of eukaryotic genomes and its dynamics are of functional importance for gene expression, DNA replication, and segregation. Structural maintenance of chromosome (SMC) complexes are essential instruments of chromosome folding, enabling long-distance intra-chromatid DNA loops. The interplay between these processes is complex. For instance, cohesin, in addition to tethering sister chromatids, dynamically regulates gene expression in mammals by promoting interactions between distal regulatory elements and promoters, whereas transcription itself affects genome folding in many ways. Here, we comprehensively dissect the relative contributions of transcription and cohesin complexes, as well as their interplay, to yeast S. cerevisiae genome organization. In particular, we show that transcription (1) is not a motor required to push cohesin during DNA loop expansion, (2) specifically induces the appearance of DNA loops independently of SMC complexes, and (3) interferes with cohesin-mediated DNA loop expansion during their establishment.

Long interspersed nuclear element 1 (L1) retrotransposons represent a vast source of genetic variability. However, mechanistic analysis of whether and how L1s contribute to human developmental programs is lacking, in part due to the challenges associated with specific profiling and manipulation of human L1 expression. Here, we show that thousands of hominoid-specific L1 integrants are expressed in human induced pluripotent stem cells and cerebral organoids. The activity levels of individual L1 promoters vary widely and correlate with an active epigenetic state. Efficient on-target CRISPR interference (CRISPRi) silencing of L1s revealed nearly a hundred co-opted L1-derived chimeric transcripts, and L1 silencing resulted in changes in neural differentiation programs and reduced cerebral organoid size. Together, these data implicate L1s and L1-derived transcripts in hominoid-specific CNS developmental processes.

The Yellow and Yangtze river basins in China are among the world's oldest independent agricultural centers, known for the domestication of millet and rice, respectively, yet their genetic history is poorly understood. Here, we present genome-wide data from 74 Middle Neolithic genetic samples from these regions, showing marked genetic differentiation but bidirectional gene flow, supporting a demic diffusion model of mixed farming. Yellow River populations exhibit distinct genetic substructures resulting from interactions with surrounding groups during the mid-Neolithic expansion of millet agriculture. Upper Yellow River populations are genetically linked to Tibetan Plateau populations and possess the earliest adaptive EPAS1 haplotype (∼5,800 BP) among modern humans. Meanwhile, Yangtze River rice farmers show genetic affinity with Neolithic to present-day southeast coastal China and Austronesian populations, tracing the origins of proto-Austronesians farther north to the Yangtze River. These findings offer new insights into the impact of mid-Neolithic agricultural expansion on human genetic history.

The NPIP gene family is among the most positively selected gene families in humans/apes and drives independent duplication in primate lineages. These duplications promote genetic instability, leading to recurrent disease-associated microduplication and microdeletion syndromes. Despite its importance, little is known about its function or variation in humans, as short-read sequencing cannot distinguish high-identity duplications. Using long-read assemblies of 169 human haplotypes, we find extreme variation in the content and organization of NPIP loci. We identify fixed and polymorphic paralogs and observe ongoing positive selection. With long-read RNA sequencing (RNA-seq), we create paralog-specific gene models, the majority of which were not previously documented, and observe paralog-specific tissue specificity. This analysis of an exceptionally dynamic gene family provides candidates for future functional study.

Urine contains fragments of cell-free DNA (cfDNA) that offer molecular insights into processes within the urinary system and the body. It remains unclear whether these fragments exist as chromatin and retain chromatin modifications from their cells of origin. Here, we employ cell-free chromatin immunoprecipitation followed by sequencing (cfChIP-seq) on human urine to address this issue. We show that cf-nucleosomes can be captured from urine and preserve histone modifications associated with gene activation and repression. Analysis in healthy individuals reveals distinct tissue contributions to urine cf-nucleosomes, including a kidney-derived population not detected in matched exfoliated cells or plasma. This suggests that kidney filtration largely excludes plasma cf-nucleosomes. In patients with bladder cancer, urine cf-nucleosomes reflect tumor-associated transcriptional programs and immune responses. These findings highlight the utility of urine cf-nucleosomes as accessible, non-invasive biomarkers for studying renal physiology and monitoring urinary pathologies.

Psoriasis vulgaris (PsV) is an immune-mediated inflammatory skin disorder with complex genetic architecture. Most genome-wide association studies (GWASs) of PsV have been limited to analyzing common single-nucleotide variants in Europeans, lacking diversity in the variant spectrum and ancestral background. To investigate the contribution of rare variants (RVs) and structural variants (SVs), we perform a whole-genome sequencing study involving 1,415 PsV cases and 3,968 controls in Japanese. A GWAS signal at IFNLR1 is fine-mapped to a 3.3-kb deletion SV disrupting an epithelium-specific putative enhancer, which is validated by PacBio long-read sequencing. Gene-based RV analyses identify two susceptibility genes: IFIH1 (p = 9.8 × 10^-6) and CERCAM (p = 4.1 × 10^-7). Notably, IL36RN, a causative gene for generalized pustular psoriasis, a rare and lethal multi-systemic inflammatory disorder, is associated with common PsV (p = 1.2 × 10^-4). Finally, Cercam knockout (Cercam^-/-) in an imiquimod-induced psoriasis mouse model aggravates dermatitis with elevated T cell retention in the subepidermis. Our study elucidates the overlooked genetic basis of PsV.