Biology subjects

Zhou, L.

Publications and source records attributed to Zhou, L..

At least 235 records · Page 13Linked to original sources

bioRxiv2021

A synthetic lethal screen identifies HDAC4 as a potential target in MELK overexpressing cancers

Maternal embryonic leucine zipper kinase (MELK) is frequently overexpressed in cancer, but the role of MELK in cancer is still poorly understood. MELK was shown to have roles in many cancer-associated processes including tumor growth, chemotherapy resistance, and tumor recurrence. To determine whether the frequent overexpression of MELK can be exploited in therapy, we performed a high-throughput screen using a library of Saccharomyces cerevisiae mutants to identify genes whose functions become essential when MELK is overexpressed. We identified two such genes: LAG2 and HDA3. LAG2 encodes an inhibitor of the SCF ubiquitin-ligase complex, while HDA3 encodes a subunit of the HDA1 histone deacetylase complex. We find that one of these synthetic lethal interactions is conserved in mammalian cells, as inhibition of a human homolog of HDA3 (HDAC4) is synthetically toxic in MELK overexpression cells. Altogether, our work might provide a new angle of how to exploit MELK overexpression in cancers and might thus lead to novel intervention strategies.

genetics↗

bioRxiv2021

DeeReCT-TSS: A novel meta-learning-based method annotates TSS in multiple cell types based on DNA sequences and RNA-seq data

The accurate annotation of transcription start sites (TSSs) and their usage is critical for the mechanistic understanding of gene regulation under different biological contexts. To fulfill this, on one hand, specific high-throughput experimental technologies have been developed to capture TSSs in a genome-wide manner. On the other hand, various computational tools have also been developed for in silico prediction of TSSs solely based on genomic sequences. Most of these computational tools cast the problem as a binary classification task on a balanced dataset and thus result in drastic false positive predictions when applied on the genome-scale. To address these issues, we present DeeReCT-TSS, a deep-learning-based method that is capable of TSSs identification across the whole genome based on both DNA sequences and conventional RNA-seq data. We show that by effectively incorporating these two sources of information, DeeReCT-TSS significantly outperforms other solely sequence-based methods on the precise annotation of TSSs used in different cell types. Furthermore, we develop a meta-learning-based extension for simultaneous transcription start site (TSS) annotation on 10 cell types, which enables the identification of cell-type-specific TSS. Finally, we demonstrate the high precision of DeeReCT-TSS on two independent datasets from the ENCODE project by correlating our predicted TSSs with experimentally defined TSS chromatin states. Our application, pre-trained models and data are available at https://github.com/JoshuaChou2018/DeeReCT-TSS_release.

bioinformatics↗

bioRxiv2021

A connectome-based neuromarker of the non-verbal number acuity and arithmetic skills

The approximate number system (ANS) is vital for survival and reproduction in animals and crucial in constructing abstract mathematical abilities in humans. Most previous neuroimaging studies focused on identifying discrete brain regions responsible for the ANS and characterizing their functions in numerosity perception. However, there lacks a neuromarker to characterize an individuals ANS acuity, especially one based on the whole-brain functional connectivity (FC). Here, we identified a distributed brain network (i.e., numerosity network) using a connectome-based predictive modeling (CPM) analysis on the resting-state functional magnetic resonance imaging (rs-fMRI) data based on a large sample size. The summed strength of all FCs within the numerosity network could reliably predict individual differences of the ANS acuity in behavior. Furthermore, in an independent dataset from the Human Connectome Project (HCP), we found that the summed FC strength within the numerosity network could also predict individual differences in arithmetic skills. Our findings illustrate that the numerosity network we identified could be an applicable neuromarker of the non-verbal number acuity and might serve as the neural basis underlying the known link between the non-verbal number acuity and mathematical abilities.

neuroscience↗

bioRxiv2021

A recombinant protein containing influenza viral conserved epitopes and superantigen induces broad-spectrum protection

Influenza pandemic poses public health threats annually for lacking vaccine which provides cross-protection against novel and emerging influenza viruses. Combining conserved antigens inducing cross-protective antibody response with epitopes activating cross-protective cytotoxic T-cells would offer an attractive strategy for developing universal vaccine. In this study, we constructed a recombinant protein NMHC consisting of influenza viral conserved epitopes and superantigen fragment. NMHC promoted the mature of bone marrow-derived dendritic cells and induced CD4+ T cells to differentiate into Th1, Th2 and Th17 subtypes. Mice vaccinated with NMHC produced high level of immunoglobulins which cross-bound to HA fragments from six influenza virus subtypes with high antibody titers. Anti-NMHC serum showed potent hemagglutinin inhibition effects to highly divergent group 1 (H1 subtypes) and group 2 (H3 subtype) influenza virus strains. And purified anti-NMHC antibodies could bind to multiple HAs with high affinities. NMHC vaccination effectively protected the mice from infection and lung damage challenged by two subtypes of H1N1 influenza virus. Moreover, NMHC vaccination elicited CD4+ and CD8+ T-cell responses to clear the virus from infected tissue and prevent virus spreading. In conclusion, this study provided proof of concept for triggering both B cells and T cells immune responses against multiple influenza virus infection, and NMHC may be a potential candidate of universal broad-spectrum vaccine for various influenza virus prevention and therapy.

epidemiology↗

bioRxiv2021

Combinatorial small molecule-mediated activation of CBP/p300 with environmental enrichment in chronic severe experimental spinal cord injury to enable axon regeneration and sprouting for functional recovery

The interruption of spinal circuitry following spinal cord injury disrupts neural activity and is followed by a failure to mount an effective regenerative gene expression response resulting in permanent neurological disability. Functional recovery requires the enhancement of axonal and synaptic plasticity of spared as well as injured fibres, which need to sprout and/or regenerate to form new connections. Here we will investigate whether the combined epigenetic stimulation of the regenerative gene expression program with neuronal activity-dependent enhancement of neuroplasticity and guidance can overcome the current inability to promote neurological recovery in severe and chronic spinal cord injury. This will be carried out by delivering the small molecule CBP/p300 activator CSP-TTK21 in combination with environmental enrichment. We will deliver the CBP/p300 activator CSP-TTK21 weekly between week twelve and twenty following a severe transection model of spinal cord injury in the mouse. Data analysis will assess modifications in regenerative signalling, in motor and sensory axon sprouting and regeneration, in synaptic plasticity as well as in neurological sensorimotor recovery. This approach will advance our mechanistic understanding of regenerative failure and provide insight of whether combining growth promoting strategies with enhancement of neural activity is an effective therapeutic strategy in chronic spinal cord injury.

neuroscience↗

bioRxiv2021

A subset of CB002 xanthine analogues bypass p53-signaling to restore a p53 transcriptome and target an S-phase cell cycle checkpoint in tumors with mutated-p53

Mutations in TP53 occur commonly in the majority of human tumors and confer aggressive tumor phenotypes including metastasis and therapy resistance. CB002 and structural-analogues restore p53 signaling in tumors with mutant-p53 but we find that unlike other xanthines such as caffeine, pentoxifylline, and theophylline, they do not deregulate the G2-checkpoint. Novel CB002-analogues induce pro-apoptotic Noxa protein in an ATF3/4-dependent manner, whereas caffeine, pentoxifylline, and theophylline do not. By contrast to caffeine, CB002-analogues target an S-phase checkpoint associated with increased p-RPA/RPA2, p-ATR, decreased Cyclin A, p-histone H3 expression and downregulation of essential proteins in DNA-synthesis and -repair. CB002-analogue #4 enhances cell death, and decreases Ki-67 in patient-derived tumor-organoids without toxicity to normal human cells. Preliminary in vivo studies demonstrate anti-tumor efficacy in mice. Thus, a novel class of anti-cancer drugs show activation of p53 pathway signaling in tumors with mutated p53, and target an S-phase checkpoint.

cancer biology↗

bioRxiv2021

Saturation variant interpretation using CRISPR prime editing

Over the last decade, next generation sequencing has become widely implemented in clinical practice. However, as genetic variants of uncertain significance (VUS) are frequently identified, the need for scaled functional interpretation of such variants has become increasingly apparent. One method to address this is saturation genome editing (SGE), which allows for scaled multiplexed functional assessment of single nucleotide variants. The current applications of SGE, however, rely on homology-directed repair (HDR) to introduce variants of interest, which is limited by low editing efficiencies and low product purity. Here, we have adapted CRISPR prime editing for SGE and demonstrated its utility in understanding the functional significance of variants in the NPC1 gene underlying the lysosomal storage disorder Niemann-Pick disease type C1 (NPC). Additionally, we have designed a genome editing strategy that allows for the haploidization of gene loci, which permits isolated variant interpretation in virtually any cell type. By combining saturation prime editing (SPE) with a clinically relevant assay, we have functionally scored and interpreted 256 variants in NPC1 haploidized HEK293T cells. To further demonstrate the applicability of this strategy, we used SPE and cell model haploidization to functionally score 465 variants in the BRCA2 gene. We anticipate that our work will be translatable to any gene with an appropriate cellular assay, allowing for more rapid and accurate diagnosis and improved genetic counselling and ultimately precise patient care.

genetics↗

bioRxiv2021

Emerged human-like facial expression representation in a deep convolutional neural network

Face identity and expression play critical roles in social communication. Recent research found that the deep convolutional neural networks (DCNNs) trained to recognize facial identities spontaneously learn features that support facial expression recognition, and vice versa, suggesting an integrated representation of facial identity and expression. In the present study, we found that the expression-selective units spontaneously emerged in a VGG-Face trained for facial identity recognition and tuned to distinct basic expressions. Importantly, they exhibited typical hallmarks of human expression perception, i.e., the facial expression confusion effect and categorical perception effect. We then investigated whether the emergence of expression-selective units is attributed to either face-specific experience or domain-general processing, by carrying out the same analysis on a VGG-16 trained for object classification and an untrained VGG-Face without any visual experience, both of them having the identical architecture with the pretrained VGG-Face. Although Similar expression-selective units were found in both DCNNs, they did not exhibit reliable human-like characteristics of facial expression perception. Taken together, our computational findings revealed the necessity of domain-specific visual experience of face identity for the development of facial expression perception, highlighting the contribution of nurture to form human-like facial expression perception. Beyond the weak equivalence between human and DCNNS at the input-output behavior, emerging simulated algorithms between models and humans could be established through domain-specific experience.

neuroscience↗

bioRxiv2021

A chromosome-level genome assembly and annotation of a maize elite breeding line Dan340

BackgroundMaize is not only one of the most important crops grown worldwide for food, forage, and biofuel, but also an important model organism for fundamental research in genetics and genomics. Owing to its importance in crop science, genetics and genomics, several reference genomes of common maize inbred line (genetic material) have been released, but some genomes of important genetic germplasm resources in maize breeding research are still lacking. The maize cultivar Dan340 is an excellent backbone inbred line of the Luda Red Cob Group with several desirable characteristics, such as disease resistance, lodging resistance, high combining ability, and wide adaptability. FindingsIn this study, we constructed a high-quality chromosome-level reference genome for Dan340 by combining PacBio long HiFi sequencing reads, Illumina short reads and chromosomal conformational capture (Hi-C) sequencing reads. The final assembly of the Dan340 genome was 2,348.72 Mb, including 2,738 contigs and 2,315 scaffolds with N50 of 41.49 Mb and 215.35 Mb, respectively. Repeat sequences accounted for 73.40% of the genome size and 39,733 protein-coding genes were annotated. Analysis of genes in the Dan340 genome, together with those from B73, Mo17 and SK, were clustered into 27,654 gene families. There were 1,806 genes from 359 gene families that were specific to Dan340, of which many had functional gene ontology annotations relating to "porphyrin-containing compound metabolic process", "tetrapyrrole biosynthetic process", and "tetrapyrrole metabolic process". ConclusionsThe completeness and continuity of the genome were comparable to those of other important maize inbred lines. The assembly and annotation of this genome not only facilitates our understanding about of intraspecific genome diversity in maize, but also provides a novel resource for maize breeding improvement. Research AreasGenetics and Genomics; Agriculture, Plant Genetics Data Description

genomics↗

bioRxiv2021

Spatially coordinated heterochromatinization of distal short tandem repeats in fragile X syndrome

Short tandem repeat (STR) instability is causally linked to pathologic transcriptional silencing in a subset of repeat expansion disorders. In fragile X syndrome (FXS), instability of a single CGG STR tract is thought to repress FMR1 via local DNA methylation. Here, we report the acquisition of more than ten Megabase-sized H3K9me3 domains in FXS, including a 5-8 Megabase block around FMR1. Distal H3K9me3 domains encompass synaptic genes with STR instability, and spatially co-localize in trans concurrently with FMR1 CGG expansion and the dissolution of TADs. CRISPR engineering of mutation-length FMR1 CGG to normal-length preserves heterochromatin, whereas cut-out to pre-mutation-length attenuates a subset of H3K9me3 domains. Overexpression of a pre-mutation-length CGG de-represses both FMR1 and distal heterochromatinized genes, indicating that long-range H3K9me3-mediated silencing is exquisitely sensitive to STR length. Together, our data uncover a genome-wide surveillance mechanism by which STR tracts spatially communicate over vast distances to heterochromatinize the pathologically unstable genome in FXS. One-Sentence SummaryHeterochromatinization of distal synaptic genes with repeat instability in fragile X is reversible by overexpression of a pre-mutation length CGG tract.

genomics↗

bioRxiv2021

Synthetic repertoires derived from convalescent COVID-19 patients enable discovery of SARS-CoV-2 neutralizing antibodies and a novel quaternary binding modality

The ongoing evolution of SARS-CoV-2 into more easily transmissible and infectious variants has sparked concern over the continued effectiveness of existing therapeutic antibodies and vaccines. Hence, together with increased genomic surveillance, methods to rapidly develop and assess effective interventions are critically needed. Here we report the discovery of SARS-CoV-2 neutralizing antibodies isolated from COVID-19 patients using a high-throughput platform. Antibodies were identified from unpaired donor B-cell and serum repertoires using yeast surface display, proteomics, and public light chain screening. Cryo-EM and functional characterization of the antibodies identified N3-1, an antibody that binds avidly (Kd,app = 68 pM) to the receptor binding domain (RBD) of the spike protein and robustly neutralizes the virus in vitro. This antibody likely binds all three RBDs of the trimeric spike protein with a single IgG. Importantly, N3-1 equivalently binds spike proteins from emerging SARS-CoV-2 variants of concern, neutralizes UK variant B.1.1.7, and binds SARS-CoV spike with nanomolar affinity. Taken together, the strategies described herein will prove broadly applicable in interrogating adaptive immunity and developing rapid response biological countermeasures to emerging pathogens.

synthetic biology↗

bioRxiv2021

Epigallocatechin Gallate from Green Tea Effectively Blocks Infection of SARS-CoV-2 and New Variants by Inhibiting Spike Binding to ACE2 Receptor

As the COVID-19 pandemic rages on, the new SARS-CoV-2 variants have emerged in the different regions of the world. These newly emerged variants have mutations in their spike (S) protein that may confer resistance to vaccine-elicited immunity and existing neutralizing antibody therapeutics. Therefore, there is still an urgent need of safe, effective, and affordable agents for prevention/treatment of SARS-CoV-2 and its variant infection. Here, we demonstrated that green tea beverage (GTB) or its major ingredient, epigallocatechin gallate (EGCG), were highly effective in inhibiting infection of live SARS-CoV-2 and human coronavirus (HCoV OC43). In addition, infection of the pseudoviruses with spikes of the new variants (UK-B.1.1.7, SA-B.1.351, and CA-B.1.429) was efficiently blocked by GTB or EGCG. Among the 4 active green tea catechins at noncytotoxic doses, EGCG was the most potent in the action against the viruses. The highest inhibitory activity was observed when the viruses or the cells were pre-incubated with EGCG prior to the infection. Mechanistic studies revealed that EGCG blocked infection at the entry step through interfering with the engagement of the receptor binding domain (RBD) of the viral spikes to angiotensin-converting enzyme 2 (ACE2) receptor of the host cells. These data support further clinical evaluation and development of EGCG as a novel, safe, and cost-effective natural product for prevention/treatment of SARS-CoV-2 transmission and infection.

microbiology↗

bioRxiv2021

RBPMS2 is a conserved regulator of alternative splicing that promotes myofibrillar organization and optimal calcium handling in cardiomyocytes

RationaleThe identification of novel cardiomyocyte-intrinsic factors that support heart function will expand the number of candidate genes and therapeutic options for heart failure, a leading cause of death worldwide. ObjectiveTo identify and characterize conserved regulators of cardiomyocyte function. Methods and ResultsWe report that the RNA-binding protein RBPMS2 is required for myofibril organization and the regulation of intracellular calcium dynamics in both zebrafish embryos and human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). A differential expression screen in zebrafish uncovered enrichment of rbpms2 paralogs, rbpms2a and rbpms2b, in the myocardium. Double knock-out (rbpms2-null) embryos suffer from compromised ventricular filling during the relaxation phase of the cardiac cycle, which significantly reduces cardiac output. Whole transcriptome sequencing and validation studies revealed differential alternative splicing of several genes linked to cardiomyopathies in humans, including myosin binding protein C3 (mybpc3) and phospholamban (pln), consistent with a role in causing the observed ventricular deficiencies. Further, RBPMS2-null hiPSC-CMs exhibit myofibril and calcium handling defects that are highly analogous to those observed in the rbpms2-null zebrafish ventricle. ConclusionsTaken together, our data identify RBPMS2 as a conserved and essential regulator of alternative splicing that is required for myofibrillar organization and optimal calcium handling from zebrafish to humans.

developmental biology↗

bioRxiv2021

ER exit sites in Drosophila display abundant ER-Golgi vesicles and pearled tubes but no megacarriers

Secretory cargos are collected at ER exit sites (ERES) before transport to the Golgi apparatus. Decades of research have provided many details of the molecular events underlying ER-Golgi exchanges. Essential questions, however, remain about the organization of the ER-Golgi interface in cells and the type of membrane structures mediating traffic from ERES. To investigate these, we used transgenic tagging in Drosophila flies, 3D-SIM and FIB-SEM to characterize ERES-Golgi units in collagen-producing fat body, imaginal discs and imaginal discs overexpressing ERES determinant Tango1. We found in front of ERES a pre-cis-Golgi region involved in both anterograde and retrograde transport. This pre-cis-Golgi is continuous with the rest of the Golgi, not a separate intermediate compartment or collection of large carriers, for which we found no evidence. We found, however, many vesicles, as well as pearled tubules connecting ERES and Golgi.

cell biology↗

bioRxiv2021

N6-methyladenosine RNA modification regulates strawberry fruit ripening in an ABA-dependent manner

BackgroundEpigenetic marks, such as DNA methylation, play pivotal roles in regulating ripening of both climacteric and non-climacteric fruits. However, it remains unclear whether mRNA m6A methylation, the epitranscriptome, is functionally conserved for ripening control. ResultsHere we show that m6A methylation, which has been revealed to regulate ripening of tomato, a typical climacteric fruit, displays a dramatic change at ripening onset of strawberry, a classical non-climacteric fruit. The m6A modification in the coding sequence (CDS) regions appears to be ripening-specific and tends to stabilize the mRNAs, whereas m6A around the stop codons and within the 3 untranslated regions is generally negatively correlated with the abundance of the mRNAs. We identified thousands of transcripts with m6A hypermethylation in the CDS regions, including those of NCED5, ABAR, and AREB1 in the abscisic acid (ABA) biosynthesis and signaling pathway. We demonstrated that the methyltransferases MTA and MTB are indispensable for normal ripening of strawberry fruit, and MTA-mediated m6A modification promotes mRNA stability of NCED5 and AREB1, while facilitates translation of ABAR. ConclusionOur findings uncover that m6A methylation regulates ripening of non-climacteric strawberry fruit by targeting ABA pathway, which is distinct from that in climacteric tomato fruit.

developmental biology↗

bioRxiv2021

Ontoclick: a Chrome web browser extension to facilitate biomedical knowledge curation

Knowledge curation from the biomedical literature is very valuable but can be a repetitive and laborious process. The paucity of user-friendly tools is one of the reasons for the lack of widespread adoption of good biomedical knowledge curation practices. Here we present Ontoclick, a web browser extension that streamlines the process of annotating a text span with a relevant ontology term. We hope this tool will make biocuration more accessible to a wider audience of biomedical researchers. Ontoclick is freely available under the GPL-3.0 license on the Chrome Web Store and on the Mozilla Add-Ons for Firefox Store. Source code and documentation are available at: https://github.com/azankl/Ontoclick Contact: andreas.zankl@sydney.edu.au

bioinformatics↗

bioRxiv2021

Recovery of high-qualitied Genomes from a deep-inland Salt Lake Using BASALT

Metagenomic binning enables the in-depth characterization of microorganisms. To improve the resolution and efficiency of metagenomic binning, BASALT (Binning Across a Series of AssembLies Toolkit), a novel binning toolkit was present in this study, which recovers, compares and optimizes metagenomic assembled genomes (MAGs) across a series of assemblies from short-read, long-read or hybrid strategies. BASALT incorporates self-designed algorithms which automates the separation of redundant bins, elongate and refine best bins and improve contiguity. Evaluation using mock communities revealed that BASALT auto-binning obtained up to 51% more number of MAGs with up to 10 times better MAG quality from microbial community at low (132 genomes) and medium (596 genomes) complexity, compared to other binners such as DASTool, VAMB and metaWRAP. Using BASALT, a case-study analysis of a Salt Lake sediment microbial community from northwest arid region of China was performed, resulting in 426 non-redundant MAGs, including 352 and 69 bacterial and archaeal MAGs which could not be assigned to any known species from GTDB (ANI < 95%), respectively. In addition, two Lokiarchaeotal MAGs that belong to superphylum Asgardarchaeota were observed from Salt Lake sediment samples. This is the first time that candidate species from phylum Lokiarchaeota was found in the arid and deep-inland environment, filling the current knowledge gap of earth microbiome. Overall, BASALT is proven to be a robust toolkit for metagenomic binning, and more importantly, expand the Tree of Life.

bioinformatics↗

bioRxiv2021

BRAF inhibitors reprogram cancer-associated fibroblasts to drive matrix remodeling and therapeutic escape in melanoma

The tumor stroma and its cellular components are known to play an important role in tumor resilience towards treatment. Here, we report a novel resistance mechanism in melanoma that is elicited by BRAF inhibitors (BRAFi)-induced non-canonical nuclear {beta}-catenin signaling in cancer-associated fibroblasts (CAFs). Our study reveals that BRAFi leads to an expanded CAF population with increased {beta}-catenin nuclear accumulation and enhances their biological properties. This CAF subpopulation is essential for melanoma cells to grow and resist to BRAFi/MEK inhibitors (MEKi). Mechanistically, BRAFi induces BRAF and CRAF dimerization and subsequently the activation of ERK signaling in CAFs, leading to the inactivation of the {beta}-catenin destruction complex. By RNA-Seq, periostin (POSTN) is identified as a major downstream effector of {beta} catenin in CAFs and can compensate for the loss of {beta}-catenin in CAFs in conferring melanoma cell BRAFi/MEKi resistance. Moreover, POSTN reactivates the ERK pathway, which is inhibited by BRAFi/MEKi, in melanoma cells through PI3K/AKT signaling. Our data underscore the roles of BRAFi-induced CAF reprogramming in matrix remodeling and therapeutic escape of melanoma cells and reveal POSTN as an important matrix target to eliminate BRAFi/MEKi resistance in melanoma.

cancer biology↗