bioRxiv Science⌕ Search

Biology subjects

Jin, B.

Publications and source records attributed to Jin, B..

At least 37 records · Page 2Linked to original sources

ScRNA-seq and scATAC-seq reveal that sertoli cell mediate spermatogenesis disorders through stage-specific communications in non-obstructive azoospermia

Non-obstructive azoospermia (NOA) belongs to male infertility due to spermatogenesis failure. However, evidence for cell type-specific abnormalities of spermatogenesis disorders in NOA remains lacking. We performed single-cell RNA sequencing (scRNA-seq) and single-cell assay for transposase-accessible chromatin sequencing (scATAC-seq) on testicular tissues from patients with obstructive azoospermia(OA) and NOA. HE staining confirmed the structural abnormalities of the seminiferous tubules in NOA patients. We identified 12 germ cell subtypes (spermatogonial stem cell-0 (SSC0), SSC1, SSC2, diffing-spermatogonia (Diffing-SPG), diffed-spermatogonia (Diffed-SPG), pre-leptotene (Pre-Lep), leptotene-zygotene (L-Z), pachytene (Pa), diplotene (Di), spermatids-1 (SPT1), SPT2, and SPT3) and 8 Sertoli cell subtypes (SC1-SC8). Among them, three novel Sertoli cell subtypes phenotypes were identified, namely SC4/immature, SC7/mature, and SC8/further mature Sertoli cells. For each germ or Sertoli cell subtype, we identified unique new markers, among which immunofluorescence confirmed co-localization of ST3GAL4, A2M, ASB9, and TEX19 and DDX4 (classical marker of germ cell). PRAP1, BST2, and CCDC62 were co-expressed with SOX9 (classical marker of Sertoli cell) in testes tissues also confirmed by immunofluorescence. The interaction between germ cell subtypes and Sertoli cell subtypes exhibits stage-specific-matching pattern, as evidenced by SC1/2/5/7 involving in SSC0-2 development, SC3 participating in the whole process of spermiogenesis, SC4/6 participating in Diffing and Diffed-SPG development, and SC8 involving in the final stage of SPT3. This pattern of specific interactions between subtypes of germ cell and Sertoli cell was confirmed by immunofluorescence of novel markers in testes tissues. The interaction was mainly contributed by Notch1/2/3 signaling. Our study profiled the single-cell transcriptome of human spermatogenesis and provided many potentials molecular markers for developing testicular puncture specific marker kits for NOA patients. Impact statementThe specific interactions between Sertoli cell subtypes and different stages of germ subgroups maintain normal development of germ cells. SC3 subtype absence may be the key factor leading to NOA.

cell biology↗

A developmental brain-wide screen identifies retrosplenial cortex as a key player in the emergence of persistent memory

Memories formed early in life are short-lived while those formed later persist. Recent work revealed that infant memories are stored in a latent state. But why they fail to be retrieved is poorly understood. Here we investigated brain-wide circuit mechanisms underlying infantile amnesia. We performed a screen that combined contextual fear conditioning, activity-dependent neuronal tagging at different postnatal ages, tissue clearing and light sheet microscopy. We observed striking developmental changes in regional activity patterns between infant, juvenile, and adult mice, including changes in the retrosplenial cortex (RSP) that aligned with the emergence of persistent memory. We then performed a series of targeted investigations of RSP structure and function across development. Chronic chemogenetic reactivation of tagged RSP ensembles during the week after learning enhanced memory in adults and juveniles, but not in infants. However, after 33 days, reactivating infant-tagged RSP ensembles recovered forgotten memories. Changes in the developmental functions of RSP memory ensembles were accompanied by changes in dendritic spine density and the likelihood that those ensembles could be reactivated by contextual cues. These studies show that RSP ensembles store latent infant memories, reveal the time course of RSP functional maturation, and suggest that immature RSP functional networks contribute to infantile amnesia.

neuroscience↗

A CAG repeat threshold for therapeutics targeting somatic instability in Huntington's disease

The Huntingtons disease mutation is a CAG repeat expansion in the huntingtin gene that results in an expanded polyglutamine tract in the huntingtin protein. The CAG repeat is unstable, and expansions of hundreds of CAGs have been detected in Huntingtons disease post-mortem brains. The age of disease onset can be predicted partially from the length of the CAG repeat as measured in blood. Onset age is also determined by genetic modifiers, which in six cases involve variation in DNA mismatch repair pathways genes. Knocking-out specific mismatch repair genes in mouse models of Huntingtons disease prevents somatic CAG repeat expansion. Taken together, these results have led to the hypothesis that somatic CAG repeat expansion in Huntingtons disease brains is required for pathogenesis. Therefore, the pathogenic repeat threshold in brain is longer than (CAG)40, as measured in blood, and is currently unknown. The mismatch repair gene MSH3 has become a major focus for therapeutic development, as unlike other mismatch repair genes, nullizygosity for MSH3 does not cause malignancies associated with mismatch repair deficiency. Potential treatments targeting MSH3 currently under development include gene therapy, biologics and small molecules, which will be assessed for efficacy in mouse models of Huntingtons disease. The zQ175 knock-in model carries a mutation of approximately (CAG)185 and develops early molecular and pathological phenotypes that have been extensively characterised. Therefore, we crossed the mutant huntingtin allele onto heterozygous and homozygous Msh3 knock-out backgrounds to determine the maximum benefit of targeting Msh3 in this model. Ablation of Msh3 prevented somatic expansion throughout the brain and periphery, and reduction of Msh3 by 50% decreased the rate of expansion. This had no effect on the deposition of huntingtin aggregation in the nuclei of striatal neurons, nor on the dysregulated striatal transcriptional profile. This contrasts with ablating Msh3 in knock-in models with shorter CAG repeat expansions. Therefore, further expansion of a (CAG)185 repeat in striatal neurons does not accelerate the onset of molecular and neuropathological phenotypes. It is striking that highly expanded CAG repeats of a similar size in humans cause disease onset before 2 years of age, indicating that somatic CAG repeat expansion in the brain is not required for pathogenesis. Given that the trajectory for somatic CAG expansion in the brains of Huntingtons disease mutation carriers is unknown, our study underlines the importance of administering treatments targeting somatic instability as early as possible.

neuroscience↗

Electron-bifurcation and fluoride efflux systems in Acetobacterium spp. drive defluorination of perfluorinated unsaturated carboxylic acids

Enzymatic cleavage of C-F bonds in per- and polyfluoroalkyl substances (PFAS) is largely unknown but avidly sought to promote systems biology for PFAS bioremediation. Here, we report the reductive defluorination of , {beta}-unsaturated per- and polyfluorocarboxylic acids by Acetobacterium spp. Two critical molecular features in Acetobacterium species enabling reductive defluorination are (i) a functional fluoride efflux transporter (CrcB) and (ii) an electron-bifurcating caffeate reduction pathway (CarABCDE). The fluoride transporter was required for detoxification of released fluoride. Car enzymes were implicated in defluorination by the following evidence: (i) only Acetobacterium spp. with car genes catalyzed defluorination; (ii) caffeate and PFAS competed in vivo; (iii) models from the X-ray structure of the electron-bifurcating reductase (CarC) positioned the PFAS substrate optimally for reductive defluorination; (iv) products identified by 19F-NMR and high-resolution mass spectrometry were consistent with the model. Defluorination biomarkers identified here were found in wastewater treatment plant metagenomes on six continents.

microbiology↗

SCFFBXW11 complex targets interleukin-17 receptor A for ubiquitin-proteasome-mediated degradation.

Interleukin-17 (IL-17) is a pro-inflammatory cytokine, participating in innate and adaptive immune responses, that plays an important role in host defense, autoimmune diseases, tissue regeneration, metabolic regulation, and tumor progression. Post-translational modifications (PTMs) are crucial for protein function, stability, cellular localization, cellular transduction, and cell death. However, PTMs of IL-17 receptor A (IL-17RA) have not been investigated. Here, we showed that human IL-17RA was targeted by F-box and WD repeats domain containing 11 (FBXW11) for ubiquitination, followed by proteasome-mediated degradation. We used bioinformatics tools and biochemical techniques to determine that FBXW11 ubiquitinated IL-17RA through a lysine 27-linked polyubiquitin chain, targeting IL-17RA for proteasomal degradation. Domain 665-804 of IL-17RA was critical for interaction with FBXW11 and subsequent ubiquitination. Our study demonstrates that FBXW11 regulates IL-17 signaling pathways at IL-17RA level.

biochemistry↗

Directing polymorph specific calcium carbonate formation with de novo protein templates

Biomolecules modulate inorganic crystallization to generate hierarchically structured biominerals1-5, but the atomic structure of the organic-inorganic interfaces that regulate mineralization remain unknown6-8. We hypothesized that heterogeneous nucleation of calcium carbonate could be achieved by a structured flat molecular template that pre-organizes calcium ions on its surface. To test this hypothesis, we designed helical repeat proteins (DHRs) displaying regularly spaced carboxylate arrays on their surfaces and found that both protein monomers and protein-Ca2+ assemblies directly nucleate nano-calcite with non-natural (110) or (202) faces while vaterite, which forms first absent the proteins, is bypassed. The nanocrystals then assemble by oriented attachment into calcite mesocrystals. We find further that nanocrystal size and polymorph can be tuned by varying the length and surface chemistry of the designed protein templates. Thus, bio-mineralization can be programmed using de novo protein design, providing a route to next-generation hybrid materials. One sentence summaryDe novo designed protein templates promote nucleation of nano-calcite and direct its growth by oriented particle attachment.

biochemistry↗

Testing a candidate meiotic drive locus identified by pool sequencing

Meiotic drive biases the transmission of alleles in heterozygous individuals, such that Mendels law of equal segregation is violated. Most examples of meiotic drive have been discovered over the past century based on causing sex-ratio distortion or the biased transmission of easily scoreable genetic markers that were linked to drive alleles. More recently, several approaches have been developed that attempt to identify distortions of Mendelian segregation genome-wide. Here we test a candidate female meiotic drive locus in Drosophila melanogaster, identified previously as causing a [~]54:46 distortion ratio using sequencing of large pools of backcross progeny. We inserted fluorescent visible markers near the candidate locus and scored transmission in thousands of individual progeny. We observed a small but significant deviation from the Mendelian expectation, however it was in the opposite direction to that predicted based on the original experiments. We discuss several possible causes of the discrepancy between the two approaches, noting that subtle viability effects are particularly challenging to disentangle from potential small-effect meiotic drive loci. We conclude that pool sequencing approaches remain a powerful method to identify candidate meiotic drive loci, but that genotyping of individual progeny at early developmental stages may be required for robust confirmation.

genetics↗

Anionic Phospholipids Control Mechanisms of GPCR-G Protein Recognition

G protein-coupled receptors (GPCRs) are embedded in phospholipids that strongly influence drug-stimulated signaling. Anionic lipids are particularly important for GPCR signaling complex formation, but a mechanism for this role is not understood. Using NMR spectroscopy, we visualized the impact of anionic lipids on the function-related conformational equilibria of the human A2A adenosine receptor (A2AAR) in bilayers containing defined mixtures of zwitterionic and anionic phospholipids. Anionic lipids primed the receptor to form complexes with G proteins through a conformational selection process. Without anionic lipids, signaling complex formation proceeded through a less favorable induced fit mechanism. In computational models, anionic lipids mimicked interactions between a G protein and positively charged residues in A2AAR at the receptor intracellular surface, stabilizing a pre-activated receptor conformation. Replacing these residues strikingly altered the receptor response to anionic lipids in experiments. High sequence conservation of the same residues among all GPCRs supports a general role for lipid-receptor charge complementarity in signaling.

biophysics↗

Transposable elements drive the evolution of metazoan zinc finger genes

Cys2-His2 Zinc finger genes (ZNFs) form the largest family of transcription factors in metazoans. ZNF evolution is highly dynamic and characterized by the rapid expansion and contraction of numerous subfamilies across the animal phylogeny. The forces and mechanisms underlying rapid ZNF evolution remain poorly understood, but there is growing evidence that the targeting and repression of lineage-specific transposable elements (TEs) plays a major role in the diversification of the Kruppel-associated box ZNF (KZNF) subfamily, which predominates in tetrapod genomes. At present, it is unknown whether this function and co-evolutionary relationship is unique to KZNFs, or a broader feature of metazoan ZNFs. Here, we present evidence that genomic conflict with TEs has been a central driver in the diversification of ZNFs in animals. Sampling from more than 4000 animal genome assemblies, we show that the copy number of retroelements correlates with that of ZNFs across at least 750 million years of metazoan evolution, both within and between major taxonomic groups. Using computational predictions, we show that ZNFs preferentially bind TEs in a diverse set of representative animal species. We further investigate one of the most expansive ZNF subfamilies found in cyprinid fish, which are characterized by a conserved domain we dubbed the Fish N-terminal Zinc-finger associated (FiNZ) domain. FiNZ-ZNFs have dramatically expanded in several fish species, including the zebrafish in which we predict ~700 FiNZ-ZNF genes. Almost all are located on the long arm of chromosome 4, and recent duplicates are evolving adaptively under positive selection. Like mammalian KZNFs, the bulk of zebrafish FiNZ-ZNFs are expressed in waves at the onset of zygotic genome activation. Blocking FiNZ-ZNF translation using morpholinos during early zebrafish embryogenesis results in a global de-repression of young, transcriptionally active TEs, likely driven by the failure to establish heterochromatin over these elements. Together, these data suggest that ZNF diversification has been intimately connected to TE expansion throughout animal evolution and that families of ZNFs have been deployed independently in fish and mammals to repress TEs during early embryogenesis.

genomics↗

A new concept in antiviral drug design

Contemporary antiviral development, whether by rational drug design or forward pharmacology, primarily strives to produce lock and key inhibitors. While the technology to identify druggable targets and create compounds to bind them has improved dramatically over the last century it has always been constrained by the finite availability of suitable binding sites that antiviral compounds can occupy. Here we present a new approach to drug design that utilizes compounds devised to alter the microenvironment of the virion surface making it incompatible with virus entry and illustrate this strategy with inhibitors of influenza virus. We show that compounds that produce a proton-rich mantle above the virion surface induce a conformational change in the viral hemagglutinin (HA) rendering the virus unable to interact with cellular receptors and gain entry to the cell. The compounds show exceptional antiviral activity both in vitro and in vivo and protect against influenza illness in mice and ferrets after a single dose, either therapeutically or prophylactically. The work presented here lays the foundation for a brand-new category of inhibitors that could be engineered to counter many different viruses and potentially other pathogens.

microbiology↗

Allelic Transcription Factor binding shape transcriptional kinetics in human cell lines

Gene expression from bulk RNA-seq studies is an average measurement between two chromosomes and across cell populations. Both allelic and cell-to-cell heterogeneity in gene expression results from promoter bursting patterns that repeatedly alternate between an activated and inactivated state. Increased cell-to-cell heterogeneity in gene expression has been associated with aging and stem cell pluripotency. However, studies of bursting kinetics and their molecular mechanism are relatively limited in human cells compared to other species due to laborious single-molecule experiments. Here, we systematically investigate the regulatory effect of genetic variants and transcription factor (TF) binding on transcriptional kinetics at the single chromosome level with GM12878. We found that the transcription initiation rate and burst frequency correlate most with eQTL effect sizes among transcriptional kinetics, which suggests that eQTLs affect average gene expression mainly through altering burst kinetics. We further found that [~]90% of the variance of burst frequency can be explained by TF occupancy in phase with the core promoter. We identified and replicated several examples where eQTL or GWAS catalog loci perturb TF binding affinity and are consequently associated with the change of burst kinetics.

genetics↗

COEVOLUTION WITH SPATIALLY STRUCTURED RICE LANDRACES MAINTAINS MULTIPLE GENERALIST LINEAGES IN THE RICE BLAST PATHOGEN

Traditional agrosystems, where humans, crops and microbes have coevolved over long periods, can serve as models to understand the eco-evolutionary determinants of disease dynamics and help the engineering of durably resistant agrosystems. Here, we investigated the genetic and phenotypic relationship between rice (Oryza sativa) landraces and their rice blast pathogen (Magnaporthe oryzae) in the traditional Yuanyang terraces of flooded rice paddies in China, where rice landraces have been grown and bred over centuries without significant disease outbreaks. Analyses of genetic subdivision revealed that indica rice plants clustered according to landrace names. Three new diverse lineages of rice blast specific to the Yuanyang terraces coexisted with lineages previously detected at the worldwide scale. Population subdivision in the pathogen population did not mirror pattern of population subdivision in the host. Measuring the pathogenicity of rice blast isolates on landraces revealed generalist life histories. Our results suggest that the implementation of disease control strategies based on the emergence or maintenance of a generalist lifestyle in pathogens may sustainably reduce the burden of disease in crops.

evolutionary biology↗

CHIQUITA1 maintains temporal transition between proliferation and differentiation in Arabidopsis thaliana

Body size varies widely among species, populations, and individuals depending on the environment. Transitioning between proliferation and differentiation is a crucial determinant of final organ size, but how the timing of this transition is established and maintained remains unknown. Using cell proliferation markers and genetic analysis, we show that CHIQUITA1 (CHIQ1) is required to maintain the timing of the transition from proliferation to differentiation in Arabidopsis thaliana. Combining kinematic and cell lineage tracking studies, we found that the number of actively dividing cells in chiquita1-1 plants decreases prematurely compared to wild type plants, suggesting CHIQ1 maintains the proliferative capacity in dividing cells and ensures that cells divide a certain number of times. CHIQ1 belongs to a plant-specific gene family of unknown molecular function and physically and genetically interacts with three close members of its family to control the timing of proliferation exit. Our work reveals the interdependency between cellular and organ-level processes underlying final organ size determination. SignificanceTiming of the transition between proliferation and differentiation is fundamental for determining the final size of organs and organisms. In agriculture, controlling organ and organism size can influence key agronomic traits such as yield and biomass. Dwarfism prevents lodging and was the trait responsible for the Green Revolution. Today, more sophisticated traits are needed for generating crops that are both resilient and sustainable. Revealing the molecular mechanisms that control the temporal transition between proliferation and differentiation will help unlock the potential of next-generation crops. Here, we report that CHIQUITA 1 in Arabidopsis thaliana is needed to maintain the proper timing of the transition between proliferation and differentiation in leaves and roots.

plant biology↗

An Association Test of the Spatial Distribution of Rare Missense Variants within Protein Structures Improves Statistical Power of Sequencing Studies

Over 90% of variants are rare, and 50% of them are singletons in the Alzheimers Disease Sequencing Project Whole Exome Sequencing (ADSP WES) data. However, either single variant tests or unit-based tests are limited in the statistical power to detect the association between rare variants and phenotypes. To best utilize rare variants and investigate their biological effect, we exam their association with phenotypes in the context of protein. We developed a protein structure-based approach, POKEMON (Protein Optimized Kernel Evaluation of Missense Nucleotides), which evaluates rare missense variants based on their spatial distribution on the protein rather than allele frequency. The hypothesis behind this is that the three-dimensional spatial distribution of variants within a protein structure provides functional context and improves the power of association tests. POKEMON identified four candidate genes from the ADSP WES data, namely two known Alzheimers disease (AD) genes (TREM2 and SORL) and two novel genes (DUSP18 and CSF1R). For known AD genes, the signal from the spatial cluster is stable even if we exclude known AD risk variants, indicating the presence of additional low frequency risk variants within these genes. DUSP18 has a cluster of variants primarily shared by case subjects around the ligand-binding domain, and this cluster is further validated in a replication dataset with a larger sample size. POKEMON is an open-source tool available at https://github.com/bushlab-genomics/POKEMON.

bioinformatics↗

IFITM3 regulates virus-induced inflammatory cytokine production by titrating Nogo-B orchestration of TLR responses

Interferon induced transmembrane protein 3 (IFITM3) is an important viral restriction factor in viral pathogenesis that also exhibits poorly understood immune regulatory functions. Here, using human and mouse models, we demonstrate that IFITM3 regulates MyD88-dependent TLR-mediated cytokine production following dendritic cell exposure to cytomegalovirus (CMV), and this process limits viral pathogenesis in vivo. IFITM3 also restricted pro-inflammatory (IL-6) cytokine production in response to influenza. IFITM3 bound to and promoted ubiquitination and proteasomal degradation of the reticulon 4 isoform Nogo-B. We reveal that Nogo-B mediates TLR-dependent pro-inflammatory cytokine production and promotes viral pathogenesis in vivo, and this process involved alteration of TLR dynamics. The anti-inflammatory function of IFITM3 was intrinsically linked to its ability to regulate Nogo-B. Thus, we uncover Nogo-B as an unappreciated driver of viral pathogenesis and highlight a novel immune regulatory pathway where IFITM3 fine-tunes TLR responsiveness of myeloid cells to viral stimulation.

immunology↗

BehaviorDEPOT: a tool for automated behavior classification and analysis in rodents

Quantitative descriptions of animal behavior are essential to understand the underlying neural substrates. Many behavioral analyses are performed by hand or with expensive and inflexible commercial software that often fail on animals with attached head implants, such as those used for in vivo optogenetics and calcium imaging. With the development of machine learning algorithms that can estimate animal positions across time and space, it is becoming easier for users with no prior coding experience to perform automated animal tracking in behavioral video recordings. Yet classifying discrete behaviors based on positional tracking data remains a significant challenge. To achieve this, we must start with reliable ground truth definitions of behavior, a process that is hindered by unreliable human annotations. To overcome these barriers, we developed BehaviorDEPOT (DEcoding behavior based on POsitional Tracking), a MATLAB-based application comprising six independent modules and a graphical user interface. In the Analysis Module we provide hard-coded classifiers for freezing and rearing. Optionally applied spatiotemporal filters allow users to analyze behaviors in varied experimental designs (e.g. cued tasks or optogenetic manipulations). Even inexperienced users can generate organized behavioral data arrays that can be seamlessly aligned with neurophysiological recordings for detailed analyses of the neural substrates. Four additional modules create an easy-to-use pipeline for establishing reliable ground-truth definitions of behaviors as well as custom behavioral classifiers. Finally, our Experiment Module runs fear conditioning experiments using an Arduino-based design that interfaces with commercialhardware and significantly reduces associated costs. We demonstrate the utility and flexibility of BehaviorDEPOT in widely used behavioral assays including fear conditioning, avoidance, and decision-making tasks. We also demonstrate the robustness of the BehaviorDEPOT freezing classifier across multiple camera types and in mice and rats wearing optogenetic patch cables and head-mounted Miniscopes. BehaviorDEPOT provides a simple, flexible, automated pipeline to move from pose tracking to reliably quantifying a wide variety of task-relevant behaviors.

neuroscience↗

A Bivalent Chromatin Controls Timing of Expression of Camalexin Biosynthesis Genes in Response to a Pathogen Signal in Arabidopsis

Temporal dynamics of gene expression underpins the responses to internal and environmental stimuli. In eukaryotes, regulation of gene induction includes changing chromatin states at the target genes, and recruitment of the transcriptional machinery that includes transcription factors. As one of the most potent specialized metabolites in Arabidopsis thaliana, camalexin can be rapidly induced by bacterial and fungal infections. Though several transcription factors controlling camalexin biosynthesis genes have been characterized, it remains unknown how the rapid activation of genes in this pathway upon a pathogen signal happens. By combining publicly available epigenomic data with in vivo chromatin mapping, we found that camalexin biosynthesis genes are marked with two epigenetic modifications with opposite effects on gene expression, H3K27me3 (repression) and H3K18ac (activation), to form a bivalent chromatin. Mutants with reduced H3K27m3 or H3K18ac showed that both modifications were required to determine the timing of gene expression and metabolite accumulation at an early stage of the stress response. Our study indicates that this type of bivalent chromatin, which we name a kairostat, plays an important role controlling the timely induction of gene expression upon stimuli in plants.

plant biology↗

The jasmine (Jasminum sambac) genome and flower fragrances

Jasminum sambac, a world-renowned plant appreciated for its exceptional flower fragrance, is of cultural and economic importance. However, the genetic basis of its fragrance is largely unknown. Here, we present the first de novo genome of J. sambac with 550.12 Mb (scaffold N50 = 40.1 Mb) assembled into 13 pseudochromosomes. Terpene synthase genes associated with flower fragrance are significantly amplified in the form of gene clusters through tandem duplications in the genome. Eleven homolog genes within the SABATH super-family were identified as related to phenylpropanoid/benzenoid compounds. Several key genes regulating jasmonate biosynthesis were duplicated causing increased copy numbers. Furthermore, multi-omics analyses identified various aromatic compounds and the key genes involved in fragrance biosynthesis pathways. Our genome of J. sambac offers a basic genetic resource for studying floral scent biosynthesis and provides an essential foundation for functional genomic research and variety improvements in Jasminum.

plant biology↗