Biology subjects

Guo, J.

Publications and source records attributed to Guo, J..

At least 163 records · Page 9Linked to original sources

bioRxiv2024

Production of four-gene (GTKO/hCD55/hTBM/hCD39)-edited donor pigs and kidney xenotransplantation

BackgroundThe number of multigene-modified donor pigs for xenotransplantation is increasing with the advent of gene editing technologies. However, which gene combination is suitable for which organ transplantation remains unclear. MethodsIn this study, we utilized CRISPR/Cas9 gene editing technology, PiggyBac transposon system and somatic cell cloning to construct GTKO/hCD55/hTBM/hCD39 four-gene-edited cloned (GEC) pigs and performed kidney transplantation from pig to rhesus monkey to evaluate the effectiveness of these GEC pigs. ResultsFirst, 107 cell colonies were obtained through drug selection, of which 7 were 4-GE colonies. Two colonies were selected for somatic cell nuclear transfer, resulting in 7 fetuses, of which 4 were GGTA1 biallelic knockout. Both fetuses had higher expression of hCD55, hTBM and hCD39. Therefore, these two fetuses were selected for two consecutive rounds of cloning, resulting in a total of 97 live piglets. After phenotype identification, the GGTA1 gene of these pigs was inactivated, and hCD55, hTBM and hCD39 were expressed in cells and multiple tissues. Furthermore, the numbers of monkey IgM and IgG binding to the peripheral blood mononuclear cells (PBMCs) of the 4-GEC pigs were markedly reduced. Moreover, 4-GEC porcine PBMCs had greater survival rates than those from wild-type pigs through complement-mediated cytolysis assays. In pig-to-monkey kidney xenotransplantation, the kidney xenograft successfully survived for 11 days. All physiological and biochemical indicators were normal, and no hyperacute rejection or coagulation abnormalities were found after transplantation. ConclusionThese results indicate that the GTKO/hCD55/hTBM/hCD39 four-gene modification effectively alleviates immune rejection, and the pig kidney can functionally support the recipient monkeys life.

genetics↗

bioRxiv2024

Production and functional verification of 8-gene (GGTA1, CMAH, β4GalNT2, hCD46, hCD55, hCD59, hTBM, hCD39)-edited donor pigs for xenotransplantation

Gene-edited pig-to-human xenotransplantation continues to make breakthroughs and is expected to enter clinic to solve the global shortage of donor organs. However, which gene combination is suitable for which organ transplantation remains unclear. In this study, we utilized CRISPR/Cas9 gene editing technology, PiggyBac transposon system and somatic cell cloning to construct GTKO/CMAHKO/{beta}4GalNT2KO/hCD46/hCD55/hCD59/hCD39/hTBM 8 gene-edited cloned (GEC) donor pigs, and performed pig to non-human primate (NHP) transplantation to evaluate the effectiveness of these GEC pigs. The multiple vectors were co-transfected into fetal fibroblasts of Diannan miniature pig with O blood type, and 25 colonies were screened out, and one of them carried GGTA1, CMAH and {beta}4GalNT2 biallelic knockout and integration of hCD46, hCD55, hCD59, hTBM and hCD39 genes, which was used as a donor cell for cloning, and a 33-day-old viable fetus was obtained. The fetus was identified and confirmed for normal karyotype and the absence of three xenogeneic antigens -Gal, Neu5Gc and Sda, and expression of hCD46, hCD55, hCD59, hTBM and hCD39 genes, then the recloning was carried out and 28 cloned piglets were obtained by natural delivery. Molecular identification at DNA, mRNA and protein levels showed that 8 gene editing (GE) was successful in these GEC piglets. Moreover, antigen-antibody binding assay and complement-dependent cytotoxicity assay demonstrated that 8GE effectively reduced the immune incompatibility and kidney xenograft survived up to 15 and 17 days into two NHPs, respectively. During this period, the recipient serum antibodies IgA and IgM, complements C3 and C4, coagulation indicators PT, APTT, TT and FIB, as well as most electrolytes and liver function indicators remained relatively stable. The 24-hour urine output and serum creatinine remained normal at a period of post-transplantation. These results indicated that the 8GEC pigs effectively alleviated immune rejection and exerted life-supporting kidney function in the recipient.

genetics↗

bioRxiv2024

Unraveling the impact of hyperleptinemia on female reproduction: Insights from transgenic pig model

BackgroundInfertility is a growing global health concern affecting millions of couples worldwide. Among several factors, an extreme body weight adversely affects reproductive functions. Leptin is a well-known adipokine that serves as an endocrine signal between adiposity and fertility. However, the exact mechanisms underlying the effects of high leptin on female reproduction remain unclear. MethodsTransgenic pig overexpressing leptin (11) were produced by back cross and screened for leptin overexpression, and the growth curve, fat deposition, reproductive performance, apoptosis, serum hormones and cholesterol production, RNA sequencing, and single nucleus RNA sequencing of the leptin-overexpressed pigs and control group were evaluated. ResultsTransgenic pig overexpressing leptin (11) were obtained, which exhibited significantly reduced body weight, body size, and back fat thickness. These pigs manifested late onset of puberty (327{+/-}48.5 vs 150{+/-}6.5 days), irregular estrous behavior characterized by increased inter-estrous interval (28.1{+/-}4.2 vs 21.3 {+/-} 0.9 days), and more numbers of mating until pregnancy (at least 3 times). This reproductive impairment in leptin pigs was related to hormonal imbalances characterized by increased levels of FSH, LH, prolactin, E2, P4, and TSH, altered steroidogenesis such as increased levels of serum CE along with steroidogenic markers (STAR, CYP19A), and ovarian dysfunctions manifested by neutrophilic infiltration and low expression of caspase-3 positive cells on leptin pigs ovary. Meanwhile, bulk RNA sequencing of the ovaries also revealed neutrophilic infiltration followed by upregulation of inflammation-related genes. Further, leptin overexpression triggered immune response, suppressed follicle development and luteinization, imposing metabolism dysfunction and hormone imbalance in the ovary by single-nucleus RNA sequencing (snRNA-seq). ConclusionLow body weight in leptin overexpression pigs adversely affects reproductive performance, causing delayed puberty, irregular estrous cycles, and reduced breeding efficiency. This is linked to metabolic imbalances, increased immune response, and altered ovarian functions. This study provided a theoretical basis for the complex mechanisms underlying leptin, and infertility by employing leptin-overexpressed female pigs.

genetics↗

bioRxiv2024

RUNX2 Isoform II Protects Cancer Cells from Ferroptosis by Promoting PRDX2 Expression in Oral Squamous Cell Carcinoma

Ferroptosis is a distinct iron-dependent programmed cell death and plays important roles in tumor suppression. However, the regulatory mechanisms of ferroptosis need further exploration. RUNT-related transcription factor 2 (RUNX2), a transcription factor, is essential for osteogenesis. RUNX2 has two types of transcripts produced by two alternative promoters. In the present study, we surprisingly find that RUNX2 isoform II is a novel ferroptosis and apoptosis suppressor. RUNX2 isoform II can bind to the promoter of peroxiredoxin-2 (PRDX2), a ferroptosis inhibitor, and activate its expression. Knockdown of RUNX2 isoform II suppresses cell proliferation in vitro and tumorigenesis in vivo in oral squamous cell carcinoma (OSCC). Interestingly, homeobox A10 (HOXA10), an upstream positive regulator of RUNX2 isoform II, is required for the inhibition of ferroptosis and apoptosis through the RUNX2 isoform II/PRDX2 pathway. Consistently, RUNX2 isoform II is overexpressed in OSCC, and associated with OSCC progression and poor prognosis. Collectively, OSCC cancer cells can up-regulate RUNX2 isoform II to inhibit ferroptosis and apoptosis, and facilitate tumorigenesis through the novel HOXA10/RUNX2 isoform II/PRDX2 pathway. Research organismHuman, Mouse, Oral Squamous Cell Carcinoma

cancer biology↗

bioRxiv2024

Fast adaptive super-resolution lattice light-sheet microscopy for rapid, long-term, near-isotropic subcellular imaging

Lattice light-sheet microscopy (LLSM) provides a crucial observation window into intra- and inter-cellular physiology of living specimens with high speed and low phototoxicity, however, at the diffraction-limited resolution or anisotropic super-resolution with structured illumination. Here we present the meta-learning-empowered reflective lattice light-sheet virtual structured illumination microscopy (Meta-rLLS-VSIM), which instantly upgrades LLSM to a near-isotropic super resolution of [~]120-nm laterally and [~]160-nm axially, more than twofold improvement in each dimension, without any modification of the optical system or sacrifice of other imaging metrics. Moreover, to alleviate the tremendous demands on training data and time necessitated by existing deep-learning (DL) methods, we devised an adaptive online training approach by synergizing the front-end imaging system and back-end meta-learning framework, which reduced the total time for data acquisition and model training down to tens of seconds. With this method, a new model can be well-trained with tenfold less data and three orders of magnitude less time than current standard supervised learning. We demonstrate the versatile functionalities of Meta-rLLS-VSIM by imaging a variety of bioprocesses with ultrahigh spatiotemporal resolution for long duration of hundreds of multi-color volumes, characterizing the dynamic regulation of contractile ring filaments during mitosis and the growth of pollen tubes, and delineating the nanoscale distributions, dispersion, and interaction pattern of multiple organelles in embryos and eukaryotic cells.

biophysics↗

bioRxiv2024

Unraveling Morphogenesis, Starvation, and Light Responses in a Mushroom-Forming Fungus, Coprinopsis cinerea, Using Long Read Sequencing and Extensive Expression Profiling

Mushroom-forming fungi (Agaricomycetes) are emerging as pivotal players in several fields, as drivers of nutrient cycling, sources of novel applications, and the group includes some of the most morphologically complex multicellular fungi. Genomic data for Agaricomycetes are accumulating at a steady pace, however, this is not paralleled by improvements in the quality of genome sequence and associated functional gene annotations, which leaves gene function notoriously poorly understood in comparison with other fungi and model eukaryotes. We set out to improve our functional understanding of the model mushroom Coprinopsis cinerea by integrating a new, chromosome-level assembly with high-quality gene predictions and functional information derived from gene-expression profiling data across 67 developmental, stress, and light conditions. The new annotation has considerably improved quality metrics and includes 5- and 3-untranslated regions (UTRs), polyadenylation sites (PAS), upstream ORFs (uORFs), splicing isoforms, conserved sequence motifs (e.g., TATA and Kozak boxes) and microexons. We found that alternative polyadenylation is widespread in C. cinerea, but that it is not specifically regulated across the various conditions used here. Transcriptome profiling allowed us to delineate core gene sets corresponding to carbon starvation, light-response, and hyphal differentiation, and uncover new aspects of the light-regulated phases of life cycle. As a result, the genome of C. cinerea has now become the most comprehensively annotated genome among mushroom-forming fungi, which will contribute to multiple rapidly expanding fields, including research on their life history, light and stress responses, as well as multicellular development.

genomics↗

bioRxiv2024

Ancient cyanobacterial proto-circadian clock adapted to short day-night cycles ~ 0.95 billion years ago

In the early history, the Earth rotation was much faster; however, how ancient organisms adapted to the day-night cycles of that time remains unclear. We resurrected the ancestor KaiABC (anKaiABC) genes circa 0.95 billion years (Ga) ago when the daily-night cycling period was [~] 18 h. Compared with its contemporary counterpart KaiC, the anKaiC protein shows subtle structural differences, and the activities of kinase, phosphatase activities, and adenosine triphosphatase (ATPase) of anKaiC are lower. The anKaiAB proteins are less effective in regulating KaiC/anKaiC phosphorylation status. The anKaiABC system does not sustain an endogenous oscillation but it can be entrained by an 18-h light/dark cycle. The strain expressing anKaiABC shows better adaptation under 9-h light/9-h dark cycles (LD9:9) which mimic the 18-h day-night cycles. These findings suggest that the ancient cyanobacterial proto-circadian system may not be endogenous, but it conferred the capability to adapt to daily cycles [~] 0.95 Ga ago.

evolutionary biology↗

bioRxiv2024

Glutamate (E299) is a key residue in the evolutionarily divergence of the SAM-dependent methyltransferases DnrK and RdmB in anthracycline biosynthesis

A novel sub-class of S-adenosyl-L-methionine (SAM)-dependent methyltransferases catalyze atypical chemical transformations in the biosynthesis of anthracyclines, which include antineoplastic compounds. Intriguingly, the closely related methyltransferases DnrK and RdmB have markedly divergent functions. We investigated their catalytic activities and discovered a previously unknown 10-hydroxylation activity for DnrK and 4-O-methylation activity for RdmB. Isotope-labeling demonstrated that the 10-hydroxy group introduced by DnrK is derived from water molecules while RdmB utilizes O2. A single residue, E299, was the key modulator in the differing catalytic functions of DnrK and RdmB, especially the decarboxylative oxidation activity. Furthermore, the multifunctionality of DnrK was demonstrated to be SAM-tunable and concerted, whereas RdmB activity was cofactor-dependent and stepwise. Our findings expand the versatility and importance of methyltransferases and should aid studies to enrich the structural diversity and bioactivities of anthracyclines.

biochemistry↗

bioRxiv2024

ExpOmics: a comprehensive web platform empowering biologists with robust multi-omics data analysis capabilities

MotivationHigh-throughput technologies have yielded a broad spectrum of multi-omics datasets, offering unparalleled insights into complex biological systems. However, effectively analyzing this diverse array of data presents challenges, given factors such as species diversity, data types, costs, and limitations of available tools. ResultsWe propose ExpOmics, a comprehensive web platform featuring seven applications and four toolkits with 28 customizable analysis functions, spanning various aspects of differential expression, co-expression, WGCNA analysis, feature selection, and functional enrichment analysis. ExpOmics empowers users to effortlessly upload and explore multi-omics data without organism restriction, supporting a wide array of data types including gene, mRNA, lncRNA, miRNA, circRNA, piRNA, and protein expression data. It is compatible with diverse gene nomenclatures and expression value types. Moreover, ExpOmics enables users to comprehensive analysis of 22,427 transcriptomic datasets sourced from 63 projects and 196 cancer subtypes in TCGA, discovering cancer biomarkers and targets. The analysis results from ExpOmics are visually presented in high-quality graphical formats suitable for publication, available for free download. In summary, ExpOmics can serves as a robust platform for global researchers to delve into diverse expression datasets, gain biological insights, and formulate testable hypotheses. Availability and implementationExpOmics is available at http://www.biomedical-web.com/expomics.

bioinformatics↗

bioRxiv2024

MGPfactXMBD: A Model-Based Factorization Method for scRNA Data Unveils Bifurcating Transcriptional Modules Underlying Cell Fate Determination

Manifold-learning is particularly useful to resolve the complex cellular state space from single-cell RNA sequences. While current manifold-learning methods provide insights into cell fate by inferring graph-based trajectory at cell level, challenges remain to retrieve interpretable biology underlying the diverse cellular states. Here, we described MGPfactXMBD, a model-based manifold-learning framework and capable to factorize complex development trajectories into independent bifurcation processes of gene sets, and thus enables trajectory inference based on relevant features. MGPfactXMBD offers more nuanced understanding of the biological processes underlying cellular trajectories with potential determinants. When bench-tested across 239 datasets, MGPfactXMBD showed advantages in major quantity-control metrics, such as branch division accuracy and trajectory topology, outperforming most established methods. In real datasets, MGPfactXMBD recovered the critical pathways and cell types in microglia development with experimentally valid regulons and markers. Furthermore, MGPfactXMBD discovered evolutionary trajectories of tumor-associated CD8+ T cells and yielded new subtypes of CD8+ T cells with gene expression signatures significantly predictive of the responses to immune checkpoint inhibitor in independent cohorts. In summary, MGPfactXMBD offers a manifold-learning framework in scRNA-seq data which enables feature selection for specific biological processes and contributing to advance our understanding of biological determination of cell fate.

bioinformatics↗

bioRxiv2024

Mechano-regulation of GLP-1 production by Piezo1 in intestinal L cells

Glucagon-like peptide 1 (GLP-1) is a gut-derived hormone secreted by intestinal L cells and vital for postprandial glycemic control. As open-type enteroendocrine cells, whether L cells can sense mechanical stimuli caused by chyme and thus regulate GLP-1 synthesis and secretion is unexplored. Our study showed expression of Piezo1 in intestinal L cells. Its level varied in different energy status and correlates with blood glucose and GLP-1 levels. Mice with L cell-specific loss of Piezo1 (IntL-Piezo1-/-) exhibited impaired glucose tolerance, increased body weight, reduced GLP-1 production and decreased CaMKK{beta}/CaMKIV-mTORC1 signaling pathway under normal chow diet or high fed diet. Activation of the intestinal Piezo1 by its agonist Yoda1 or intestinal bead implantation increased the synthesis and secretion of GLP-1, thus alleviated glucose intolerance in diet-induced-diabetic mice. Overexpression of Piezo1, Yoda1 treatment or stretching stimulated GLP-1 production and CaMKK{beta}/CaMKIV-mTORC1 signaling pathway, which could be abolished by knockdown or blockage of Piezo1 in primary cultured mouse L cells and STC-1 cells. These findings suggest a previously undiscovered mechano-regulation of GLP-1 production in L cells, which may shed new light on the treatments of diabetes.

physiology↗

bioRxiv2024

TLR2 Supports γδ T cell IL-17A Response to ocular surface commensals by Metabolic Reprogramming

The ocular surface is a mucosal barrier tissue colonized by commensal microbes, which tune local immunity by eliciting IL-17 from conjunctival {gamma}{delta} T cells to prevent pathogenic infection. The commensal Corynebacterium mastitidis (C. mast) elicits protective IL-17 responses from conjunctival V{gamma}4 T cells through a combination of {gamma}{delta} TCR ligation and IL-1 signaling. Here, we identify V{gamma}6 T cells as a major C. mast-responsive subset in the conjunctiva and uncover its unique activation requirements. We demonstrate that V{gamma}6 cells require not only extrinsic (via dendritic cells) but also intrinsic TLR2 stimulation for optimal IL-17A response. Mechanistically, intrinsic TLR2 signaling was associated with epigenetic changes and enhanced expression of genes responsible for metabolic shift to fatty acid oxidation to support Il17a transcription. We identify one key transcription factor, I{kappa}B{zeta}, which is upregulated by TLR2 stimulation and is essential for this program. Our study highlights the importance of intrinsic TLR2 signaling in driving metabolic reprogramming and production of IL-17A in microbiome-specific mucosal {gamma}{delta} T cells. SummaryOcular commensal Corynebacterium mastitidis (C. mast) induces IL-17 responses from {gamma}{delta} T cells by activating TLR2 signaling. {gamma}{delta} T cell-intrinsic TLR2 stimulation can increase Il17a transcription and promote fatty acid oxidation, favoring {gamma}{delta} T cell IL-17A responses. Highlights(1) V{gamma}6 T cells are a major C. mast-responsive subset in the conjunctiva (2) TLR2-deficient mice exhibit reduced {gamma}{delta} T cell responses to ocular commensal bacteria. (3) {gamma}{delta} T cell-intrinsic TLR2 deficiency causes defects of fatty acid oxidation and IL-17A production in a {gamma}{delta} subset-specific manner. (4) The transcription factor, I{kappa}B{zeta} is upregulated by TLR2 stimulation and supports {gamma}{delta} IL-17A production through fatty acid oxidation. O_FIG O_LINKSMALLFIG WIDTH=178 HEIGHT=200 SRC="FIGDIR/small/587519v2_ufig1.gif" ALT="Figure 1"> View larger version (44K): org.highwire.dtl.DTLVardef@1d1ba87org.highwire.dtl.DTLVardef@2d17d9org.highwire.dtl.DTLVardef@78e846org.highwire.dtl.DTLVardef@1d96dc2_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2024

Granzyme B-based CAR T cells block metastasis by eliminating circulating tumor cells

Chimeric antigen receptor (CAR) T cells have limited efficacy against solid tumors due to the hostile microenvironment. Circulating tumor cells (CTCs) are essential to metastasis, which is the cause of most of cancer-related death. Here, we generated GrB-CAR T cells targeting membrane-bound HSP70 (mHSP70), a highly tumor-specific antigen detected in numerous cancers. GrB-CAR T cells exhibited potent cytotoxicity against a broad spectrum of cancer cell lines and stem-like cancer cells in vitro and effectively inhibited xenograft tumor growth in vivo. Importantly, GrB-CAR T cells markedly decreased the number of CTCs and, therefore, hindered cancer metastasis in spontaneous metastasis models with uncontrollable primary tumor growth, a scenario commonly encountered in clinical trials of CAR T therapies for solid tumors. Furthermore, despite the 100% homology between human and macaque HSP70 protein, the autotransplantation of macaque T cells expressing human GrB-CAR did not cause any obvious toxic effects. These results not only demonstrate GrB-CAR T cells as a safe and effective tactic with broad-spectrum anticancer activity, but also offer strong experimental evidence and proof-of-concept validation for CAR T cell-mediated metastasis inhibition by targeting CTCs.

immunology↗

bioRxiv2024

GGCX promotes Eurasian avian-like H1N1 swine influenza virus adaption to interspecies receptor binding

The Eurasian avian-like (EA) H1N1 swine influenza virus (SIV) possesses the capacity to instigate the next influenza pandemic, owing to its heightened affinity for the human-type -2,6 sialic acid (SA) receptor. Nevertheless, the molecular mechanisms underlying the switch in receptor binding preferences of EA H1N1 SIV remain elusive. In this study, we conducted a comprehensive genome-wide CRISPR/Cas9 knockout screen utilizing EA H1N1 SIV in porcine kidney cells. Knocking out the enzyme gamma glutamyl carboxylase (GGCX) reduced virus replication in vitro and in vivo by inhibiting the carboxylation modification of viral haemagglutinin (HA) and the adhesion of progeny viruses, ultimately impeding the replication of EA H1N1 SIV. Furthermore, GGCX was revealed to be the determinant of the D225E substitution of EA H1N1 SIV, and GGCX-medicated carboxylation modification of HA 225E contributed to the receptor binding adaption of EA H1N1 SIV to the -2,6 SA receptor. Taken together, our CRISPR screen has elucidated a novel function of GGCX in the support of EA H1N1 SIV adaption for binding to -2,6 SA receptor. Consequently, GGCX emerges as a prospective antiviral target against the infection and transmission of EA H1H1 SIV.

microbiology↗

bioRxiv2024

The Diversified Astrocyte Developmental Programs are Modulated by Primary Ciliary Signaling

Astrocyte diversity is greatly influenced by local environmental modulation. Here, we report that the vast majority of brain astrocytes across the entire brain possess a singular primary cilium, a specialized signaling antenna localized to cell soma. Comparative single-cell transcriptomics reveals that primary cilia mediate canonical Shh signaling to modulate astrocyte subtype-specific core features in synaptic regulation, intracellular transport, energy and metabolism. Independent of canonical Shh signaling, primary cilia are important regulators for astrocyte morphology and intracellular signaling balance. Dendritic spine analysis and transcriptomics reveal that perturbation of astrocytic cilia leads to disruption of neuronal development and global intercellular connectomes in the brain. Ultimately, mice with primary ciliary deficient astrocytes show behavioral deficits in sensorimotor function, sociability, learning and memory. Our results uncover a critical role for primary cilia in transmitting local cues that drive the region-specific diversification of astrocytes within the developing brain.

neuroscience↗

bioRxiv2024

Enhancing Gastrodin Production in Yarrowia lipolytica by Metabolic Engineering

Gastrodin, 4-hydroxybenzyl alcohol-4-O-{beta}-D-glucopyranoside, has been widely used in the treatment of neurogenic and cardiovascular diseases. Currently, gastrodin biosynthesis has been achieved in model microorganisms. However, the production levels are insufficient for industrial applications. In this study, we successfully engineered a Yarrowia lipolytica strain to overproduce gastrodin through metabolic engineering. Initially, the engineered strain expressing the heterologous gastrodin biosynthetic pathway, which comprises chorismate lyase, carboxylic acid reductase, phosphopantetheinyl transferase, endogenous alcohol dehydrogenases, and a UDP-glucose dependent glucosyltransferase, produced 1.05 g/L of gastrodin from glucose in a shaking flask. Then, the production was further enhanced to 6.68 g/L with a productivity of 2.23 g/L/day by over-expressing the key node DAHP synthases of the shikimate pathway and alleviating the native tryptophan and phenylalanine biosynthetic pathways. Finally, the best strain, Gd07, produced 13.22 g/L of gastrodin in a 5-L fermenter. This represents the highest reported production of gastrodin in an engineered microorganism to date, marking the first successful de novo production of gastrodin using Y. lipolytica. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=82 SRC="FIGDIR/small/584284v1_ufig1.gif" ALT="Figure 1"> View larger version (25K): org.highwire.dtl.DTLVardef@1eddb6corg.highwire.dtl.DTLVardef@e0bd94org.highwire.dtl.DTLVardef@be472dorg.highwire.dtl.DTLVardef@32fe9d_HPS_FORMAT_FIGEXP M_FIG C_FIG

synthetic biology↗

bioRxiv2024

Molecular insights into the atypical activation mechanism of GPR156 in maintaining auditory function

The class C orphan GPCR GPR156, which lacks the typical extracellular region, plays a pivotal role in auditory function through Gi2/3. Here, we demonstrate that GPR156 with high constitutive activity is essential for maintaining auditory function, and we further present two cryo-EM structures of human GPR156. The GPR156 dimer in both the apo state and Gi3 protein-coupled state adopt a TM5/6-TM5/6 interface, indicating the high constitutive activity of GPR156 in the apo state. The C-terminus plays a dual role in promoting G protein binding within G-bound subunit while preventing the G-free subunit from binding to additional G protein. These observations explain how GPCR activity is maintained through dimerization and provide a mechanistic insight into the sustained role of GPR156 in maintaining auditory function.

molecular biology↗

bioRxiv2024

Effect of the SAS chromatin-remodeling complex on chromatin accessibility during flower development

While the role of transcription factors in flower development is well understood, the impact of chromatin remodeling on this process remains largely unclear. We conducted a comprehensive analysis to investigate the coordination of the SAS, BAS, and MAS-type SWI/SNF chromatin-remodeling complexes with transcription factors to regulate chromatin accessibility and gene transcription during flower development in Arabidopsis thaliana. Our findings indicate that the SAS complex binds to numerous genes related to flower development and is responsible for establishing chromatin accessibility of these genes during flower development. In contrast, the BAS and MAS complexes exhibit minimal involvement in regulating the accessibility of these genes. The SAS-bound genomic regions and the SAS-dependent accessible regions are enriched with sites occupied by multiple MADS family transcription factors involved in flower development. Furthermore, we found that the SAS-dependent accessibility is indispensable for the genomic binding of the MADS transcription factor AP1 at these regions. This study highlights the dynamic role of the SAS complex in modulating the genomic binding of transcription factors during plant development. One-sentence summaryThe SAS-type SWI/SNF complex regulates Inflorescence-specific chromatin accessibility at distal promoter and upstream intergenic regions, thereby facilitating the binding of transcription factors involved in flower development.

plant biology↗