Biology subjects

Bai, Y.

Publications and source records attributed to Bai, Y..

At least 145 records · Page 8Linked to original sources

bioRxiv2023

Detecting Full-Length EccDNA with FLED and long-reads sequencing

Reconstructing the full-length sequence of extrachromosomal circular DNA (eccDNA) from short sequencing reads has proved challenging given the similarity of eccDNAs and their corresponding linear DNAs. Previous sequencing methods were unable to achieve high-throughput detection of full-length eccDNAs. Here we describe a new strategy that combined rolling circle amplification (RCA) and nanopore long-reads sequencing technology to generate full-length eccDNAs. We further developed a novel algorithm, called Full-Length eccDNA Detection (FLED), to reconstruct the sequence of eccDNAs. We used FLED to analyze seven human epithelial and cancer cell line samples and identified over 5,000 full-length eccDNAs per sample. The structures of identified eccDNAs were validated by both PCR and Sanger sequencing. Compared to other published nanopore-based eccDNA detectors, FLED exhibited higher sensitivity. In cancer cell lines, the genes overlapped with eccDNA regions were enriched in cancer-related pathways and cis-regulatory elements can be predicted in the up-stream or downstream of intact genes on eccDNA molecules, and the expressions of these cancer-related genes were dysregulated in tumor cell lines, indicating the regulatory potency of eccDNAs in biological processes. Our method takes advantage of nanopore long reads and enables unbiased reconstruction of full-length eccDNA sequences. FLED is imple-mented using Python3 which is freely available on GitHub (https://github.com/FuyuLi/FLED).

genomics↗

bioRxiv2023

Disease associated human TCR characterization by deep-learning framework TCR-DeepInsight

T cell function is defined by both T cell receptors (TCR) and T cell gene expression (GEX). Although single-cell technology enables the simultaneous capture of TCR and GEX information, the lack of a reference atlas and computational tools hinders our ability to uncover the fundamental TCR usage rules and to efficiently characterize disease-associated TCRs (dTCR). Here, through the collection of million-scale single-cell GEX-TCR reference atlas comprising 20 diverse disease conditions, we revealed the intrinsic features of TCR-MHC (Major Histocompatibility Complex) restriction in CD4/CD8 lineages. We observed the higher coherence for TCR/{beta} chains in memory T cells, and detected widely-existing public TCR/{beta} pairs across individuals. Building upon the reference atlas, we introduced TCR- DeepInsight, a deep-learning framework featuring a disease specificity scoring system that enables the characterization of dTCR clusters with similar GEX-TCR. Our study provides a valuable tool for researchers to analyze single-cell GEX-TCR data and identify dTCRs comprehensively and robustly.

bioinformatics↗

bioRxiv2023

Neo-functionalization and co-option of Pif genes facilitate the evolution of a novel shell microstructure in oysters

Molluscan shell, composed of a diverse range of architectures and microstructures, is a classic model system to study the relationships between molecular evolution and biomineralized structure formation. The shells of oysters differ from those of other molluscs by possessing a novel microstructure, chalky calcite, which facilitates adaptation to the sessile lifestyle. However, the genetic basis and evolutionary origin of this adaptive innovation remain largely unknown. Here, we present the first chromosome-level genome and shell proteomes of the Iwagaki oyster Crassostrea nippona. Multi-omic integrative analyses revealed that independently evolved and co-opted genes as well as lineage-specific domains are involved in the formation of chalky layer in the oysters. Rapid mineralization involving chalky calcite are essential for reconstruction of the shell. Importantly, von Willebrand factor type A and chitin-binding domains are identified as basic members of molluscan biomineralization toolkit. We show that the well-known Pif shared a common origin in the last common ancestor of Bilateria. Furthermore, Pif and LamG3 genes acquire new genetic function for shell mineralization in bivalves and the chalky layer formation in oysters through a combination of gene duplication and domain reorganization. Our findings highlight neo-functionalization as a crucial mechanism for shell diversity, which may be applied more widely for studies on the evolution of metazoan biomineralization. This study also has potential implications for material science and biomimetic research.

evolutionary biology↗

bioRxiv2023

The DEAD-box helicase RCF1 plays roles in miRNA biogenesis and RNA splicing in Arabidopsis

RCF1 is a highly conserved DEAD-box helicase found in yeast, plants and mammals. Studies about the functions of RCF1 in plants are limited. Here we uncovered the functions of RCF1 in Arabidopsis thaliana as a player in pri-miRNA processing and splicing, as well as in pre-mRNA splicing. A mutant with miRNA biogenesis defects was isolated and the defect was traced to a recessive point mutation in RCF1 (rcf1-4). We show that RCF1 promotes D-body formation and facilitates the interaction between pri-miRNAs and HYL1. Finally, we show that intron-containing pri-miRNAs and pre-mRNAs exhibit a global splicing defect in rcf1-4. Together, this work uncovers roles for RCF1 in miRNA biogenesis and RNA splicing in Arabidopsis. One-sentence summaryRCF1 promotes not only the processing of pri-miRNAs, but also the splicing of intron-containing pri-miRNAs, therefore promotes miRNA biogenesis.

plant biology↗

bioRxiv2023

Circular RNAs in the human brain are tailored to neuron identity and neuropsychiatric disease

Little is known about circular RNAs (circRNAs) in specific brain cells and human neuropsychiatric disease. Here, we systematically identified over 11,039 circRNAs expressed in vulnerable dopamine and pyramidal neurons laser-captured from 190 human brains and non-neuronal cells using ultra-deep, total RNA sequencing. 1,526 and 3,308 circRNAs were custom-tailored to the cell identity of dopamine and pyramidal neurons and enriched in synapse pathways. 88% of Parkinsons and 80% of Alzheimers disease-associated genes produced circRNAs. circDNAJC6, produced from a juvenile-onset Parkinsons gene, was already dysregulated during prodromal, onset stages of common Parkinsons disease neuropathology. Globally, addiction-associated genes preferentially produced circRNAs in dopamine neurons, autism-associated genes in pyramidal neurons, and cancers in non-neuronal cells. This study shows that circular RNAs in the human brain are tailored to neuron identity and implicate circRNA- regulated synaptic specialization in neuropsychiatric diseases.

genomics↗

bioRxiv2023

Quorum-sensing gene regulates hormetic effects induced by sulfonamides in Comamonadaceae

Hormesis is a toxicological phenomenon whereby exposure to low-dose stress results in stimulation of various biological endpoints. Among these, the induction of cell proliferation by antibiotics is critical, but the underlying molecular mechanisms remain poorly understood. Here, we showed that sulfonyl-containing chemicals (e.g., sulfonamides) can induce cell-proliferation hormesis of Comamonas testosteroni. Investigation of the hormesis mechanism revealed that low-dose sulfonamides bind to the LuxR-type quorum sensing protein LuxR solo, thereby triggering the transcription of 3-ketoacyl-CoA thiolase, a key enzyme of the fatty acid {beta}-oxidation. This provides additional ATP, NADPH, and acetyl-CoA for purine and pyrimidine biosynthesis, allowing cells to synthesize sufficient nucleotides to support rapid cell growth. Our work reports on a previously unknown mechanism for the hormetic effect and highlights its generality in the Comamonadaceae family.

microbiology↗

bioRxiv2023

StereoCell enables high accuracy single cell segmentation for spatial transcriptomic dataset

BackgroundOwing to recent advances in resolution and field-of-view, spatially resolved transcriptomics sequencing, such as Stereo-seq, has emerged as a cutting-edge technology for the interpretation of large tissues at the single-cell level. To generate accurate single-cell spatial gene expression profiles from high-resolution spatial omics data, a powerful computational tool is required. FindingsWe present CellBin, an image-facilitated one-stop pipeline for high-resolution and large field-of-view spatial transcriptomic data of Stereo-seq. CellBin provides a comprehensive and systematic platform for generating high-confidence single-cell spatial gene expression profiles, which specifically includes image stitching, image registration, tissue segmentation, nuclei segmentation and molecule labeling. CellBin is user-friendly and does not require a specific level of omics and image analysis expertise. ConclusionsDuring image stitching and molecule labeling, CellBin delivers better-performing algorithms to reduce stitching error and time, in addition to improving the signal-to-noise ratio of single-cell gene expression data, in comparison with existing methods. Additionally, CellBin has been shown to obtain highly accurate single-cell spatial data using mouse brain tissue, which facilitated clustering and annotation.

bioinformatics↗

bioRxiv2023

Plant selection and ecological microhabitat drive domestications of shrub-associated microbiomes in a revegetated shrub ecosystem

Shrubs are used for revegetation of degraded dryland ecosystem worldwide and could recruit large numbers of microbes from the soil; however, the plant-associated microbiome assembly and the effect of plant introduction on the soil microbiomes are not fully understood. We detected shrub-associated microbes from five ecological microhabitats, including the leaves, litter, roots, rhizosphere, and root zone, across four xeric shrub plantations (Artemisia ordosica, Caragana korshinskii, Hedysarum mongolicum, and Salix psammophila). To detect the patterns of shrub-associated microbiome assembly, 16S and ITS2 rRNA gene sequencing was performed. PERMANOVA and differential abundance analysis demonstrated that changes in the bacterial and fungal communities were more dependent on the microhabitats rather than on the plant species, with distinct niche differentiation. Moreover, source tracking and nestedness analysis showed that shrub-associated bacteria were primarily derived from bulk soils and slightly pruned in different microhabitats; however, a similar pattern was not found for fungi. Furthermore, the surrounding zone of roots was a hotpot for microbial recruitments of revegetated shrubs. Null model analysis indicated that homogeneous selection of determinism dominated the bacterial communities, whereas dispersal limitation and undominated process of stochasticity drove the assembly of fungal communities. Our findings indicate that ecological microhabitat of revegetated shrublands was the main predictor of the bacterial and fungal compositional variances. This study will help advance our understanding of the mechanism underlying the plant-soil microbiome feedbacks during the initial plant-establishment period in a dryland ecosystem. Further, this work provides theoretical reference for establishment and sustainable management of shrublands in drylands.

microbiology↗

bioRxiv2023

Structural mechanism of LIN28B nucleosome targeting by OCT4 for pluripotency

Pioneer transcription factors are essential for cell fate changes by targeting closed chromatin. OCT4 is a crucial pioneer factor that can induce cell reprogramming. However, the structural basis of how pioneer factors recognize the in vivo nucleosomal DNA targets is unknown. Here, we determine the high-resolution structures of the nucleosome containing human LIN28B DNA and its complexes with the OCT4 DNA binding region. Three OCT4s bind the pre-positioned nucleosome by recognizing non-canonical DNA motifs. Two use their POUS domains by forming extensive hydrogen bonds. The other uses the POUS-loop-POUHD region; POUHD serves as a wedge to unwrap [~]25 base pair DNA. Biochemical studies suggest that multiple OCT4s cooperatively open the H1-condensed nucleosome array containing the LIN28B nucleosome. Our study suggests a mechanism whereby OCT4s target the LIN28B nucleosome by forming multivalent interactions with nucleosomal motifs, unwrapping nucleosomal DNA, evicting H1, and cooperatively open closed chromatin to initiate cell reprogramming.

biophysics↗

bioRxiv2022

MYSM1 co-activates ERα action via histone and non-histone deubiquitination to confer antiestrogen resistance in breast cancer

Endocrine resistance is a crucial challenge in estrogen receptor alpha (ER)-positive breast cancer (BCa) therapy. Aberrant alteration in modulation of E2/ER signaling pathway has emerged as the putative contributor for endocrine resistance in BCa. Thus, identification the efficient ER cofactor remains necessary for finding a potential therapeutic target for endocrine resistance. Herein, we have demonstrated that Myb like, SWIRM and MPN domains 1 (MYSM1) as a histone deubiquitinase is a novel ER co-activator with established Drosophila experimental model. Our results showed that MYSM1 participated in up-regulation of ER action via histone and non-histone deubiquitination. We provided the evidence to show that MYSM1 was involved in maintenance of ER stability via ER deubiquitination. Furthermore, silencing MYSM1 induced enhancement of histone H2A ubiquitination as well as reduction of histone H3K4me3 and H3Ac levels at cis regulatory elements on promoter of ER-regulated gene. In addition, MYSM1 depletion attenuated cell proliferation/growth in BCa-derived cell lines and xenograft models. Knockdown of MYSM1 increased the sensitivity of antiestrogen agents in BCa cells. MYSM1 was highly expressed in clinical BCa samples, especially in aromatase inhibitor (AI) non-responsive tissues. These findings clarify the molecular mechanism of MYSM1 as an epigenetic modifier in regulation of ER action and provide a potential therapeutic target for endocrine resistance in BCa.

cell biology↗

bioRxiv2022

DNA primase large subunit is an essential plant gene for geminiviruses, putatively priming viral ss-DNA replication

The family of Geminiviridae consists of more than 500 circular single-stranded (ss) DNA viral species that can infect numerous dicot and monocot plants. Geminiviruses replicate their genome in the nucleus of a plant cell, taking advantage of the hosts DNA replication machinery. For converting their DNA into double-stranded DNA, and subsequent replication, these viruses rely on host DNA polymerases. However, the priming of the very first step of this process, i.e. the conversion of incoming circular ssDNA into a dsDNA molecule, has remained elusive for almost 30 years. In this study, sequencing of melon (Cucumis melo) accession K18 carrying the Tomato leaf curl New Delhi virus (ToLCNDV) recessive resistance quantitative trait locus (QTL) in chromosome 11, and analyses of DNA sequence data from 100 melon genomes, showed a conservation of a shared mutation in the DNA Primase Large subunit (PRiL) of all accessions that exhibited resistance upon a challenge with ToLCNDV. Silencing of (native) Nicotiana benthamiana PriL and subsequent challenging with three different geminiviruses showed a severe reduction in titers of all three viruses, altogether emphasizing an important role of PRiL in geminiviral replication. A model is presented explaining the role of PriL during initiation of geminiviral DNA replication, i.e. as a regulatory subunit of primase that generates an RNA primer at the onset of DNA replication in analogy to DNA Primase-mediated initiation of DNA replication in all living organisms.

plant biology↗

bioRxiv2022

Mechanistic dissection of alga recognition and uptake in coral-algal endosymbiosis

Many corals form a mutually beneficial relationship with the dinoflagellate algae called Symbiodiniaceae. Cells in the coral gastrodermis recognize, phagocytose, and house the algae in an organelle called symbiosome, which supports algae photosynthesis and nutrient exchange with corals1-3. Rising ocean temperature disrupts this endosymbiotic relationship, leading to alga loss, coral bleaching and death, and the degradation of marine ecosystems4-6. Mitigation of coral death requires a mechanistic understanding of coral-algal endosymbiosis. We have developed genomic resources to enable the use of a soft coral Xenia species as a model to study coral-algal endosymbiosis7. Here we report an effective RNA interference (RNAi) method and its application in the functional studies of genes involved in early steps of endosymbiosis. We show that an endosymbiotic cell marker called LePin (for its Lectin and kazal Protease inhibitor domains) is a secreted lectin that binds to algae to initiate the formation of alga-containing endosymbiotic cells. The evolutionary conservation of LePin among marine endosymbiotic anthozoans suggests a general role in coral-algal recognition. Coupling bioinformatics analyses with RNAi and single cell (sc)-RNA-seq, we uncover three gene expression programs (GEP) influenced by LePin during the early and middle stages of endosymbiotic lineage development. Further studies of genes in these GEPs lead to the identification of two scavenger receptors that support the formation of alga-containing endosymbiotic cells, most likely by initiating phagocytosis and modulating coral immune response. We also identify two actin regulators for endosymbiosis, which shed light on the phagocytic machinery and a possible mechanism for symbiosome formation. Our findings should usher in an era of mechanistic studies of coral-algal endosymbiosis.

cell biology↗

bioRxiv2022

Spateo: multidimensional spatiotemporal modeling of single-cell spatial transcriptomics

Cells do not live in a vacuum, but in a milieu defined by cell-cell communication that can be measured via emerging high-resolution spatial transcriptomics approaches. However, analytical tools that fully leverage such data for kinetic modeling remain lacking. Here we present Spateo (aristoteleo/spateo-release), a general framework for quantitative spatiotemporal modeling of single-cell resolution spatial transcriptomics. Spateo delivers novel methods for digitizing spatial layers/columns to identify spatially-polar genes, and develops a comprehensive framework of cell-cell interaction to reveal spatial effects of niche factors and cell type-specific ligand-receptor interactions. Furthermore, Spateo reconstructs 3D models of whole embryos, and performs 3D morphometric analyses. Lastly, Spateo introduces the concept of "morphometric vector field" of cell migrations, and integrates spatial differential geometry to unveil regulatory programs underlying various organogenesis patterns of Drosophila. Thus, Spateo enables the study of the ecology of organs at a molecular level in 3D space, beyond isolated single cells.

systems biology↗

bioRxiv2022

Analysis of spatial transcriptomics at varying resolution levels using the unified framework of SpaSEG

Spatially resolved transcriptomics (SRT) for characterizing cellular heterogeneities and activities requires systematic analysis approaches to decipher gene expression variations in physiological contexts. Here we develop SpaSEG, an unsupervised convolutional neural network-based model for multiple SRT analysis tasks by jointly learning the transcriptional similarity of spots and their spatial dependence. SpaSEG adopts an edge strength constraint to encourage spatial domain coherence and allows integrative analysis by automatically aligning the spatial domains across multiple adjacent sections. It also enables the detection of domain-specific gene expression patterns and the inference of intercellular interactions and colocalizations within a tissue. In an invasive ductal carcinoma sample analysis, SpaSEG facilitates the unraveling of intratumor heterogeneity and the understanding of immunoregulatory mechanisms. Through comprehensive evaluation over a collection of SRT datasets generated by different platforms at various resolutions, SpaSEG shows superior reliability and computational efficiency over existing methods, endowing it with a great potential for the exploration of tissue architectures and pathological biology.

bioinformatics↗

bioRxiv2022

SiPLATZ12 transcript factor regulates multiple yield traits and salt tolerance in foxtail millet (Setaria italica)

Grain yield and salt tolerance are critical for crop production. However, the genetic and biochemical basis underlying the trade-off of these characters remain poorly described in crops. We show here that SiPLATZ12 transcription factor positively regulates multiple elite yield traits at the expense of salt tolerance in foxtail millet. SiPLATZ12 overexpression increases seed size, panicle length, and stem diameter, while reduces plant height and salt tolerance of foxtail millet. A 9-bp insertion in the SiPLATZ12 promoter has significant effects on the different expression of SiPLATZ12, multiple yield traits, and salt tolerance between foxtail millet and its wild ancestor, green foxtail. Moreover, SiPLATZ12 upregulates the expression of genes involved in seed development, but repressing the transcription of most NHX, SOS, and CBL genes to regulate Na+, K+ and pH homeostasis. Therefore, our results uncover a domesticated site that could be used to improve grain yield and salt tolerance in foxtail millet.

molecular biology↗

bioRxiv2022

Machine learning enables accurate prediction of breast cancer five-year survival using somatic genomic variants

Breast cancer is one of the most common cancers, accounting for about 30% of female cancers and a mortality rate of 15%. The 5-year survival rate is most commonly used to assess cancer progression and guide clinical practice. We used the CatBoost model to systematically construct a five-year mortality risk prediction model based on two independent data sets (BRCA_METABRIC, BRCA_TCGA). The model input data are the somatic genomic variants (copy number variation, SNP locus, cumulative mutation number of genes) and phenotype data of cancer samples. The optimal model combined all the above characteristics, and the AUC reached 0.70 in an independent external data set. At the same time, we also conducted a biological analysis of the characteristics of the model and found some potential biomarkers (TP53, DNAH11, MAP3K1, PHF20L1, etc.). The results of model risk stratification can be used as a guide for the prognosis of breast cancer.

bioinformatics↗

bioRxiv2022

Analysis and Identification of Necroptosis Landscape on Therapy and Prognosis in Bladder Cancer

Bladder cancer (BLCA) is one of the most common malignant tumors of the urinary system, but current therapeutic strategy based on chemotherapy and immune checkpoint inhibitors (ICIs) therapy cannot meet the treatment needs, which mainly owing to the endogenous or acquired apoptotic resistance of cancer cells. Targeting necroptosis provides a novel strategy for chemotherapy, targeted drugs, and improves the efficacy of ICIs because of strong immunogenicity of necroptosis. Therefore, we systemically analyzed necroptosis landscape on therapy and prognosis in BLCA. We firstly divided BLCA patients from The Cancer Genome Atlas (TCGA) database into two necroptosis-related clusters (C1 and C2). Necroptosis C2 showed a significantly better prognosis than C1, and the differential genes of C2 and C1 were mainly related to the immune response according to GO and KEGG analysis. Next, we constructed a novel necroptosis related genes (NRGs) signature consisting of SIRT6, FASN, GNLY, FNDC4, SRC, ANXA1, AIM2, and IKBKB to predict the survival of TCGA-BLCA cohort, the accuracy of NRGsocre was also verified by external datasets. In addition, a nomogram combining NRGscore and several clinicopathological features was established to predict the BLCA patients OS more accurately and conveniently. We also found that NRGscore was significantly related to the infiltration levels of CD8 T cells, NK cells, and iDC cells, the gene expression of CTLA4, PD1, TIGIT, and LAG3 of TME, the sensitivity to chemotherapy and targeted agents in BLCA patients. In conclusion, the NRGscore has an excellent performance in evaluating the prognosis, clinicopathologic features, tumor microenvironment (TME) and therapeutic sensitivity of BLCA patients, which could be utilized as a guide for chemotherapy, ICIs therapy, and combination therapy.

cancer biology↗

bioRxiv2022

In vivo transomic analyses of glucose-responsive metabolism in skeletal muscle reveal core differences between the healthy and obese states

Metabolic regulation in skeletal muscle is essential for blood glucose homeostasis. Obesity causes insulin resistance in skeletal muscle, leading to hyperglycemia and type 2 diabetes. In this study, we performed multiomic analysis of the skeletal muscle of wild-type (WT) and genetically obese (ob/ob) mice, and constructed regulatory transomic networks for metabolism after oral glucose administration. Our network revealed that metabolic regulation by glucose-responsive metabolites had a major effect on WT mice, especially carbohydrate metabolic pathways. By contrast, in ob/ob mice, much of the metabolic regulation by glucose-responsive metabolites was lost and metabolic regulation by glucose-responsive genes was largely increased, especially in carbohydrate and lipid metabolic pathways. We present some characteristic metabolic regulatory pathways found in central carbon, branched amino acids, and ketone body metabolism. Our transomic analysis will provide insights into how skeletal muscle responds to changes in blood glucose and how it fails to respond in obesity.

systems biology↗