Biology subjects

Kawaguchi, R. K.

Publications and source records attributed to Kawaguchi, R. K..

6 recordsLinked to original sources

bioRxiv2026

Monocyte Lineage Expansion Drives Transcriptomic Individuality in Genetically Identical Armadillo Quadruplets

Genetic diversity shapes phenotypes, yet even genetically identical individuals differ. In nine-banded armadillo (Dasypus novemcinctus) quadruplets, we previously showed that allele-specific expression (ASE) imbalances provide a stable molecular fingerprint of individuality. Here, we test whether such transcriptomic individuality reflects functional biological differences. We profiled bulk blood RNA from five cohorts of genetically identical quadruplets across three time points, and found persistent gene-expression signatures that predict individual identity. Focusing on a highly variable cohort, we then performed single-cell RNA-seq and ATAC-seq. In this litter, the most stably distinct individual showed an expanded monocyte-lineage compartment and gene-expression programs enriched for inflammatory and differentiation pathways. These cell-type and regulatory differences were stable over time and robust to experimental leprosy infection. Together, our results link transcriptomic individuality to lasting differences in immune-cell composition, illustrating how early stochastic events can produce persistent, biologically meaningful divergence among genetically identical individuals. TeaserGenetically identical armadillo quadruplets are identifiable by transcriptomic signatures shaped by cellular composition variation.

molecular biology↗

bioRxiv2025

Multiple human enhancer RNAs contain long translated open reading frames

Enhancer RNAs (eRNAs) are transcribed by RNA polymerase II during enhancer activation but are typically rapidly degraded in the nucleus. During states of reduced RNA surveillance, however, eRNAs and other similar "noncoding" RNAs, including for example upstream antisense RNAs, are stabilized, and some are exported to the cytoplasm and can even be found on polysomes. Here, we report unexpectedly that [~]12% of human intergenic eRNAs contain long open reading frames (>300 nts), many of which can be actively translated, as determined by ribosome profiling, and produce proteins that accumulate in cells, as shown by mass spectrometry (MS) data. Focusing on the largest of the encoded proteins, which we designate as eORFs, and which can be up to [~]45 KDa, we found remarkably that most are highly basic, with pIs >11.5. This unusual chemistry reflects a striking overabundance of arginine residues, and occurs despite a relative paucity of lysines. Exogenous expression of the ten largest eORFs revealed that they accumulate stably in cells as full-length proteins, and most localize to the nucleus and associate with chromatin. Identification of interacting proteins by MS suggested possible roles for these proteins in several nuclear processes. The eORFs studied are well-conserved among primates, although they are largely absent from other mammals. Notably, several contain human-specific C-terminal extensions and display properties suggestive of de novo gene birth. In summary, we have discovered that a fraction of human eRNAs can function as mRNAs, revealing a new and unexpected role for these transcripts.

molecular biology↗

bioRxiv2024

Concentration-dependent formation of intersegment interactions in viral droplets of influenza A virus infected cells

The influenza A virus genome consists of eight RNA segments, each incorporated into a virion. It has been proposed that intersegment interactions bundle these segments, and viral inclusions, which contain viral ribonucleoproteins (vRNPs) and Rab11, facilitate this process. However, the locations and mechanisms of intersegment interaction formation remain unclear. To investigate this, we identified comprehensive intersegment interactions in infected cells using customized LIGR-seq. Our results revealed that intersegment interactions in infected cells overlapped with those in the virion and were partially formed through direct RNA-RNA interactions. Additionally, we found that the formation of these interactions was delayed in cells expressing a Rab11 dominant-negative. Furthermore, artificially increasing vRNP concentrations in the nucleus, where intersegment interactions typically do not occur, triggered the formation of these interactions, which again overlapped with those in the virion. These results suggest that intersegment interactions are formed in viral inclusions where progeny vRNPs accumulate.

microbiology↗

bioRxiv2021

Prevalent and Dynamic Binding of the Cell Cycle Checkpoint Kinase Rad53 to Gene Promoters

Replication of the genome must be coordinated with gene transcription and cellular metabolism, especially following replication stress in the presence of limiting deoxyribonucleotides. The S. cerevisiae Rad53 (CHEK2 in mammals) checkpoint kinase plays a major role in cellular responses to DNA replication stress. Cell cycle regulated, genome-wide binding of Rad53 to chromatin was examined. Under replication stress, the kinase bound to sites of active DNA replication initiation and fork progression, but unexpectedly to the promoters of about 20% of genes encoding proteins involved in multiple cellular functions. Rad53 promoter binding correlated with changes in expression of a subset of genes. Rad53 promoter binding to certain genes was influenced by sequence-specific transcription factors and less by checkpoint signaling. However, in checkpoint mutants, untimely activation of late-replicating origins reduces the transcription of nearby genes, with concomitant localization of Rad53 to their gene bodies. We suggest that the Rad53 checkpoint kinase coordinates genome-wide replication and transcription under replication stress conditions.

molecular biology↗

bioRxiv2021

Exploiting marker genes for robust classification and characterization of single-cell chromatin accessibility

MotivationSingle-cell Assay for Transposase Accessible Chromatin using sequencing (scATAC-seq) is a valuable resource to learn cis-regulatory elements such as cell-type specific enhancers and transcription factor binding sites. However, cell-type identification of scATAC-seq data is known to be challenging due to the heterogeneity derived from different protocols and the high dropout rate. ResultsIn this study, we perform a systematic comparison of 7 scATAC-seq datasets of mouse brain to benchmark the efficacy of neuronal cell-type annotation from gene sets. We find that redundant marker genes give a dramatic improvement for a sparse scATAC-seq annotation across the data collected from different studies. Interestingly, simple aggregation of such marker genes achieves performance comparable or higher than that of machine-learning classifiers, suggesting its potential for downstream applications. Based on our results, we reannotated all scATAC-seq data for detailed cell types using robust marker genes. Their meta scATAC-seq profiles are publicly available at https://gillisweb.cshl.edu/Meta_scATAC. Furthermore, we trained a deep neural network to predict chromatin accessibility from only DNA sequence and identified key motifs enriched for each neuronal subtype. Those predicted profiles are visualized together in our database as a valuable resource to explore cell-type specific epigenetic regulation in a sequence-dependent and -independent manner. Contactjesse.gillis@utoronto.ca Supplementary informationSupplementary data are available at xxxxxx online. Key pointsO_LI7 scATAC-seq datasets of mouse brain are systematically compared to benchmark the efficacy of neuronal cell-type annotation from gene sets. C_LIO_LIRedundant marker genes give a dramatic improvement for a sparse scATAC-seq annotation beyond the heterogeneity of scATAC-seq data. C_LIO_LIWe reannotated all scATAC-seq data for detailed cell types using robust marker genes and their meta scATAC-seq profiles are publicly available at a new Meta scATAC-seq server. C_LIO_LIPredicted profiles from only DNA sequence using a deep neural network are visualized together to explore sequence-dependent and -independent epigenetic regulation. C_LI

bioinformatics↗

bioRxiv2020

A functional RNA structure in the influenza A virus ribonucleoprotein complex for segment bundling

The influenza A virus genome is segmented into eight viral RNAs (vRNA). Secondary structures on vRNA are thought to be involved in the viral proliferation process, such as intersegment interactions that are necessary for segment bundling. However, the functional RNA structure on vRNA is not well known because the secondary structure of vRNA in virion was partially unwound by binding viral non-specific RNA binding proteins in a sequence-independent manner. Here, we establish the global map of the vRNA secondary structure in virion using the combination of dimethyl sulfate (DMS)-seq and selective 2'-hydroxyl acylation analyzed by primer extension (SHAPE)-seq. By integrating DMS-seq and SHAPE-seq analyses with robust statistical analysis, we inferred quite a few bases paired regions including a pseudoknot structure on segment 5. Notably, when cells were infected with the recombinant virus which had mutations in the pseudoknot structure, the impairment of replication and packaging was observed on the other specific segment. Moreover, we analyzed the comprehensive intersegment RNA interactions in virion by ligation of interacting RNA followed by high-throughput sequencing (LIGR-seq). Our LIGR-seq analysis revealed that the intersegment interactions of the specific segment became less frequent and rearranged in the recombinant virus in concordance with the strength of genome packaging impairment. Our data provide evidence that the functional RNA structure motif on the influenza A virus genome can affect the efficiency of replication and segment bundling through the segment interactions.

microbiology↗