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Sun, Q.

Publications and source records attributed to Sun, Q..

At least 73 records · Page 4Linked to original sources

Dissecting dynamic gene regulatory network using transformer-based temporal causality analysis

The AI Virtual Cell (AIVC) framework promises to revolutionize biological research through high-fidelity simulations of cellular behaviors and responses to perturbations. Central to realizing this vision is the ability to model cell differentiation dynamics, which requires accurate inference of gene regulatory network (GRN) that govern cell fate decisions. However, existing computational approaches rely on static GRN models that fail to capture the dynamic changes of regulatory relationships during differentiation, limiting their utility for simulating developmental processes and predicting perturbation outcomes. Here, we present CellProphet, an interpretable AI model that infers dynamic GRN by integrating temporal causality with transformer self-attention mechanism. CellProphet captures time-lagged dependencies between transcription factor (TF) expression and target gene activation while providing interpretable regulatory weights, enabling both accurate prediction and mechanistic insight. When benchmarked against nine state-of-the-art methods across seven differentiation datasets, CellProphet achieves superior performance in all evaluation metrics. Applied to mouse embryonic stem cell differentiation, CellProphet identifies both well-known and potentially novel TFs with substantially high sensitivity and successfully reconstructs dynamic regulatory relations validated through multi-modal epigenomic data. In mouse hematopoietic differentiation, CellProphet accurately predicts cell fate transitions and gene expression changes following in silico perturbation of key TFs Gata1 and Spi1, demonstrating its capability for virtual experimentation. These results establish CellProphet as a foundational tool for the AIVC framework, enabling researchers to decode the dynamic regulatory logic of differentiation, accelerate discovery of key regulatory factors, and design targeted cellular interventions for widespread applications.

bioinformatics↗

Variational Autoencoder-based Model Improves Polygenic Prediction in Blood Cell Traits

Genetic prediction of complex traits, enabled by large-scale genomic studies, has created new measures to understand individual genetic predisposition. Polygenic Risk Scores (PRS) offer a way to aggregate information across the genome, enabling personalized risk prediction for complex traits and diseases. However, conventional PRS calculation methods that rely on linear models are limited in their ability to capture complex patterns and interaction effects in high-dimensional genomic data. In this study, we seek to improve the predictive power of PRS through applying advanced deep learning techniques. We show that the Variational AutoEncoder-based model for PRS construction (VAE-PRS) outperforms currently state-of-the-art methods for biobank-level data in 14 out of 16 blood cell traits, while being computationally efficient. Through comprehensive experiments, we found that the VAE-PRS model offers the ability to capture interaction effects in high-dimensional data and shows robust performance across different pre-screened variant sets. Furthermore, VAE-PRS is easily interpretable via assessing the contribution of each individual marker to the final prediction score through the SHapley Additive exPlanations (SHAP) method, providing potential new insights in identifying trait-associated genetic variants. In summary, VAE-PRS presents a novel measure to genetic risk prediction by harnessing the power of deep learning methods, which could further facilitate the development of personalized medicine and genetic research.

bioinformatics↗

Dissection of the Global Responses of Mandarin Fish Pyloric Caecum to An Acute Ranavirus (MRV) Infection Reveals the Formation of Serositis and Then Ascites

Mandarin fish ranavirus (MRV), a variant of largemouth bass virus (LMBV), is a distinct member of the genus Ranavirus within the family Iridoviridae. Acute MRV infection predominantly affects the pyloric caecum, a critical visceral organ in mandarin fish, and is hypothesized to drive the characteristic external clinical sign of severe ascites. In this study, we reveal that acute MRV infection initially targets the serosal layer of the pyloric caecum of mandarin fish, leading to rapid progression into fibrinous serositis characterized by serosal hypertrophy, fibrosis, hyperemia, edema, and tissue adhesions. Using single-cell RNA sequencing, we dissect the cellular composition of epithelial, immune, and stromal populations, identifying significant enrichment of macrophages and granulocytes, alongside T and natural killer cells, as key mediators of acute cytokine and inflammatory responses. Then, robust experimental evidence demonstrates that MRV attacks specific immune cell subsets of T and B cells and stromal cells of fibroblasts, myofibroblasts, endothelial cells, and pericytes, resulting in upregulation of genes and pathways associated with extracellular matrix (ECM) formation, collagen biosynthesis, and vascular remodeling in the hyperplastic serosal zone. Additionally, both host-derived type V collagens and MRV-encoded collagens are implicated in ECM formation in the hypertrophic serosa. Collectively, this study provides a comprehensive single-cell resolution analysis of the pyloric caecums response to acute MRV infection and highlights virus- driven serositis as the underlying cause of severe ascites in mandarin fish. ImportanceThe pyloric caecum is a vital digestive and immune organ in many bony fish species, including the mandarin fish, a carnivorous species with an exceptionally developed pyloric caecum comprising 207-326 caeca per individual. While MRV/LMBV infects various fish species, severe ascites is uniquely observed in infected mandarin fish. This study demonstrates that acute MRV infection induces fibrinous serositis in the pyloric caecum, characterized by hyperemia, edema, and hyperplasia, ultimately resulting in ascites and mortality. Leveraging single-cell RNA sequencing, we provide a detailed landscape of the cell types affected or involved in the inflammatory response, revealing their roles in the pathogenesis of serositis. These findings advance our understanding of MRV-induced pathology and its species-specific manifestations.

microbiology↗

Incomplete lineage sorting of segmental duplications defines the human chromosome 2 fusion site early during African great ape speciation

All great apes differ karyotypically from humans due to the fusion of chromosomes 2a and 2b, resulting in human chromosome 2. Yet, the structure, function, and evolutionary history of the genomic regions associated with this fusion remain poorly understood. Here, we analyze finished telomere-to-telomere chromosomes in great apes and macaques to show that the fusion was associated with multiple pericentric inversions, segmental duplications (SDs), and the rapid turnover of subterminal repetitive DNA. We characterized the fusion site at single-base-pair resolution and identified three distinct SDs that originated more than 5 million years ago. These three distinct SDs were differentially distributed among African great apes as a result of incomplete lineage sorting (ILS) and lineage-specific duplication. Most conspicuously, one of these SDs shares homology to a hypomethylated SD spacer sequence present in hundreds of copies in the subterminal heterochromatin of chimpanzees and bonobos. The fusion in human was accompanied by a systematic degradation of the three divergent -satellite arrays representing the ancestral centromere creating five distinct structural haplotypes in humans. CRISPR/Cas9-mediated depletion of the fusion site in human cell lines significantly alters the expression of 108 genes, indicating a potential regulatory consequence to this human-specific karyotypic change.

evolutionary biology↗

The maize recombination landscape evolved during domestication.

Meiotic recombination is an important evolutionary process because it can increase the amount of genetic variation within populations through the breakage of unfavorable linkages and creation of novel allelic combinations. Despite the plethora of knowledge about population-level benefits of recombination and numerous theoretical studies examining how recombination rates can evolve over time, there is a lack of empirical evidence for any hypotheses that have been put forward. To alleviate this gap in knowledge, we characterized the evolution of the recombination landscape in Zea mays ssp. mays (maize) during its domestication from Zea mays ssp. parviglumis (teosinte), explored hypotheses that permitted the evolution of the maize recombination landscape and tied these alterations to changes in the genetic basis of recombination. Using experimental populations and the population genomics approach of ancestral recombination graph (ARG) inference, our data demonstrated that maize had a 12% increase in its genome-wide recombination rate during domestication. Although the maize and teosinte recombination landscapes are highly correlated, r = 0.85 at 1Mb resolution, maize has evolved to have higher recombining regions in interstitial chromosome regions, compared to teosinte which only harbors high recombining regions sub-telomerically. Our data show that the re-patterning of COs towards interstitial chromosome regions came from reduced CO interference levels within maize. Supporting the idea that CO interference is reduced within maize, we found evidence for selection acting on trans-acting recombination-modifiers that participate in the class I CO pathway or CO interference directly. Lastly, we showed that the re-patterning of COs was beneficial to maize evolution because regions that significantly increased in recombination were targeted to gene-rich regions harboring domestication related loci. Because we found regions with significant increases in recombination had a lower deleterious mutation load, compared to regions with decreases in recombination, we concluded that the domestication-related variation in these regions, in which selection acted upon during domestication, was shielded from the Hill-Robertson effect. In conclusion, the re-patterning of CO events during domestication allowed maize to adapt and evolve at a faster rate than previously understood.

evolutionary biology↗

Chromatin-associated lncRNA-splicing factor condensates regulate hypoxia responsive RNA processing of genes pre-positioned near nuclear speckles

Hypoxia-induced alternative splicing (AS) regulates tumor progression and metastasis. Little is known about how such AS is controlled and whether higher-order genome and nuclear domain (ND) organizations dictate these processes. We observe that hypoxia-responsive alternatively spliced genes position near nuclear speckle (NS), the ND that enhances splicing efficiency. NS-resident MALAT1 long noncoding RNA, induced in response to hypoxia, regulates hypoxia-responsive AS. MALAT1 achieves this by organizing the SR-family of splicing factor, SRSF1, near NS and regulating the binding of SRSF1 to pre-mRNAs. Mechanistically, MALAT1 enhances the recruitment of SRSF1 to elongating RNA polymerase II (pol II) by promoting the formation of phase-separated condensates of SRSF1, which are preferentially recognized by pol II. During hypoxia, MALAT1 regulates spatially organized AS by establishing a threshold SRSF1 concentration near NSs, potentially by forming condensates, critical for pol II-mediated recruitment of SRSF1 to pre-mRNAs.

molecular biology↗

Tracing the genetic diversity of the bread wheat D genome

Bread wheat (Triticum aestivum) became a globally dominant crop after incorporating the D genome from donor species Aegilops tauschii, while evolutionary history shaping the D genome during this process remains elusive. Here, we proposed a renewed evolutionary model linking Ae. tauschii and hexaploid wheat D genome, based on an ancestral haplotype map covering a total of 762 Ae. tauschii and hexaploid wheat accessions. We dissected the evolutionary process of Ae. tauschii lineages and clarified L3 as the most ancient lineage. A few independent intermediate accessions were reported, demonstrating the low-frequent inter-sublineage geneflow enriched the diversity of Ae. tauschii. We discovered that the D genome of hexaploid wheat inherited from a unified ancestral template, but with a mosaic composition that is highly mixed by three Ae. tauschii L2 sublineages located in the Caspian coastal region, suggesting the early agricultural activities facilitate the innovation of D genome compositions that finalized the success of hexaploidization. We further found that the majority (65.6%) of polymorphisms were attributed to novel mutations absent during the spreading of bread wheat, and also identified large Ae. tauschii introgressions from wild Aegilops lineages, expanding the diversity of wheat D genome and introducing beneficial alleles. This work decoded the mystery of the wheat hexaploidization process and the evolutionary significance of the multi-layered origins of the genetic diversity of the bread wheat D genome.

evolutionary biology↗

Ground nesting of soft eggs by extinct birds and a new parity mode switch hypothesis for the evolution of animal reproduction

Nearshore ground nesting of soft eggs by extinct birds is demonstrated here, providing a new explanation for the abundance of bird fossils in early Cretaceous lacustrine environments, where humidity conditions required for soft egg incubation would have been present. This reinforces recent findings of Archaeopteryx soft eggs near Jurassic marine environments, the possibility that wings and elongated feathers developed primarily in association with nest protection on the ground and only secondarily with flight, and the origin of flight from the ground up. Notably, soft eggs preceded rigid eggs in evolution, but both crocodiles, whose ancestors seem to have antedated bird precursors, and extant birds reproduce exclusively via hard-shelled eggs. Therefore, an explanation is in order for how reproduction via soft eggs could have occurred in the bird lineage in-between two evolutionary moments of reproduction via rigid eggs. In alternative to the commonly accepted convergent evolution of viviparity and rigid eggshells, a parity mode switch hypothesis is presented here. It postulates the existence, since the rise of animals, of an inherited ancestral parity mode switch between viviparity and oviparity. This switch would have evolved to embrace hard-shelled oviparity after rigid eggshells appeared in evolution. Commitment to a particular parity mode or eggshell type may have conditioned survival of entire animal groups, especially during major extinction events, explaining, among others, the extinction of all birds that reproduced via soft eggshells.

evolutionary biology↗

Dynorphin modulates motivation through a pallido-amygdala cholinergic circuit

The endogenous opioid peptide dynorphin and its receptor {kappa}-opioid receptor (KOR) have been implicated in divergent behaviors, but the underlying mechanisms remain elusive. Here we show that dynorphin released from nucleus accumbens dynorphinergic neurons exerts powerful modulation over a ventral pallidum (VP) disinhibitory circuit, thereby controlling cholinergic transmission to the amygdala and motivational drive in mice. On one hand, dynorphin acts postsynaptically via KORs on local GABAergic neurons in the VP to promote disinhibition of cholinergic neurons, which release acetylcholine into the amygdala to invigorate reward-seeking behaviors. On the other hand, dynorphin also acts presynaptically via KORs on dynorphinergic terminals to limit its own release. Such autoinhibition keeps cholinergic neurons from prolonged activation and release of acetylcholine, and prevents perseverant reward seeking. Our study reveals how dynorphin exquisitely modulate motivation through cholinergic system, and provides an explanation for why these neuromodulators are involved in motivational disorders, including depression and addiction.

neuroscience↗

Complete enzymatic depolymerization of polyethylene terephthalate (PET) plastic using a Saccharomyces cerevisiae-based whole-cell biocatalyst

Plastics like polyethylene terephthalate (PET) have become an integral part of everyday life, yet plastic waste management remains a significant challenge. Enzymatic biocatalysis is an eco- friendly approach for recycling and upcycling of plastic waste. PET-hydrolyzing enzymes (PHEs) such as IsPETase, along with its engineered variants like FAST-PETase, demonstrate promising PET depolymerization capabilities at ambient temperatures. Whole-cell biocatalysts, displaying PHEs on their cell surface, offer high efficiency, reusability, and stability for PET depolymerization. However, their efficacy in fully breaking down PET is hindered by the necessity of two enzymes - PETase and MHETase. Current whole-cell systems either display only one PHE or struggle with performance when displaying larger passenger proteins like the MHETase-PETase chimera. In this work, we developed a Saccharomyces cerevisiae-based whole-cell biocatalyst system for complete PET depolymerization. Leveraging a cellulosome-inspired trifunctional protein scaffoldin displayed on the yeast surface, we immobilized FAST-PETase and MHETase, forming a multi-enzyme cluster. Our whole cell biocatalyst achieved complete PET depolymerization at 30{degrees}C, yielding 4.9 mM TPA in seven days with no intermediate accumulation. Furthermore, we showed improved PET depolymerization ability by binding FAST-PETase at multiple sites on the trifunctional scaffoldin. This breakthrough in complete PET depolymerization marks an essential step towards a circular plastic economy.

bioengineering↗

Inhibitor of cardiolipin biosynthesis-related enzyme MoGep4 confers broad-spectrum anti-fungal activity

Plant pathogens cause devastating diseases, leading to serious losses to agriculture. Mechanistic understanding of pathogenesis of plant pathogens lays the foundation for the development of fungicides for disease control. Mitophagy, a specific form of autophagy, is important for fungal virulence. The role of cardiolipin, mitochondrial signature phospholipid, in mitophagy and pathogenesis is largely unknown in plant pathogenic fungi. The functions of enzymes involved in cardiolipin biosynthesis and relevant inhibitors were assessed using a set of assays, including genetic deletion, plant infection, lipidomics, chemical-protein interaction, chemical inhibition, and field trials. Our results showed that the cardiolipin biosynthesis-related gene MoGEP4 of the rice blast fungus Magnaporthe oryzae regulates growth, conidiation, cardiolipin biosynthesis, and virulence. Mechanistically, MoGep4 regulated mitophagy and Mps1-MAPK phosphorylation, which are required for virulence. Chemical alexidine dihydrochloride (AXD) inhibited the enzyme activity of MoGep4, cardiolipin biosynthesis and mitophagy. Importantly, AXD efficiently inhibited the growth of 10 plant pathogens and controlled rice blast and Fusarium head blight in the field. Our study demonstrated that MoGep4 regulates mitophagy, Mps1 phosphorylation and pathogenesis in M. oryzae. In addition, we found that the MoGep4 inhibitor, AXD, displays broad-spectrum antifungal activity and is a promising candidate for fungicide development.

microbiology↗

Cell-type specific inference from bulk RNA-sequencing data by integrating single cell reference profiles via EPIC-unmix

Cell type specific (CTS) analysis is essential to reveal biological insights obscured in bulk tissue data. However, single-cell (sc) or single-nuclei (sn) resolution data are still cost-prohibitive for large-scale samples. Thus, computational methods to perform deconvolution from bulk tissue data are highly valuable. We here present EPIC-unmix, a novel two-step empirical Bayesian method integrating reference sc/sn RNA-seq data and bulk RNA-seq data from target samples to enhance the accuracy of CTS inference. We demonstrate through comprehensive simulations across three tissues that EPIC-unmix achieved 4.6% - 109.8% higher accuracy compared to alternative methods. By applying EPIC-unmix to human bulk brain RNA-seq data from the ROSMAP and MSBB cohorts, we identified multiple genes differentially expressed between Alzheimers disease (AD) cases versus controls in a CTS manner, including 57.4% novel genes not identified using similar sample size sc/snRNA-seq data, indicating the power of our in-silico approach. Among the 6-69% overlapping, 83%-100% are in consistent direction with those from sc/snRNA-seq data, supporting the reliability of our findings. EPIC-unmix inferred CTS expression profiles similarly empowers CTS eQTL analysis. Among the novel eQTLs, we highlight a microglia eQTL for AD risk gene AP3B2, obscured in bulk and missed by sc/snRNA-seq based eQTL analysis. The variant resides in a microglia-specific cCRE, forming chromatin loop with AP3B2 promoter region in microglia. Taken together, we believe EPIC-unmix will be a valuable tool to enable more powerful CTS analysis.

genomics↗

A linear sensorimotor transformation accounts for response range-dependent biases in human heading estimation

Accurate estimation of heading direction from optic flow is a crucial aspect of human spatial perception. Previous psychophysical studies have shown that humans are typically biased in their estimates of heading directions, but the reported results are inconsistent. While some studies found that humans generally underestimate heading direction (central bias), others find the opposite, an overestimation of heading direction (peripheral bias). We conducted three psychophysical experiments showing that these conflicting findings do not reflect inherent differences in heading perception but are caused by the different sizes of the response range that participants were allowed to utilize when reporting their estimates. Notably, we show that participants heading estimates monotonically scale with the size of the response range, leading to underestimation for small and overestimation for large response ranges. Additionally, neither the speed profile of the optic flow pattern nor the response method (mouse vs. keyboard) significantly affected participants estimates. Furthermore, we introduce a Bayesian heading estimation model that can quantitatively account for participants heading reports. The model assumes an efficient sensory encoding of heading direction according to a prior inferred from human heading discrimination data. In addition, the model assumes a response mapping that linearly scales the perceptual estimate with a scaling factor that monotonically depends on the size of the response range. This simple perception-action model accurately predicts participants estimates both in terms of mean and variance across all experimental conditions. Our findings underscore that human heading perception follows efficient Bayesian inference; differences in participants reported estimates can be parsimoniously explained as differences in mapping percept to probe response. Author summaryHumans can estimate the direction of their self-motion (heading) from the associated visual motion pattern (optic flow) on their retinae. While these heading estimates are typically biased, previous studies have found quite conflicting bias patterns despite using very similar optic flow stimuli. Our findings demonstrate that these differences in participants reported estimates can be attributed to differences in the response range within which participants were able to move their cursor to report their estimates. We introduce an efficient Bayesian observer model to quantitatively analyze these conflicting bias patterns. The model assumes that perceived heading directions are identical for identical optical flow patterns, yet the reported heading directions are the result of an additional response mapping that linearly maps the percept to the reported estimate. This model fits the data well and demonstrate that participants reported perceptual estimates can be substantially modulated by post-perceptual response transformations, in particular under conditions where they do not receive feedback. Our study is a reminder that psychophysical measurements necessarily provide only an indirect account of perception. Full explanations of such data require the inclusion of appropriate post-perceptual transformations that describe the mapping from perception to action.

neuroscience↗

Investigating spatial dynamics in spatial omics data with StarTrail

Spatial omics technologies revolutionize our view of biological processes within tissues. However, existing methods fail to capture localized, sharp changes characteristic of critical events (e.g. tumor development). Here, we present StarTrail, a novel gradient based method that powerfully defines rapidly changing regions and detects "cliff genes", genes exhibiting drastic expression changes at highly localized or disjoint boundaries. StarTrail, the first to leverage spatial gradients for spatial omics data, also quantifies directional dynamics. Across multiple datasets, StarTrail accurately delineates boundaries (e.g., brain layers, tumor-immune boundaries), and detects cliff genes that may regulate molecular crosstalk at these biologically relevant boundaries but are missed by existing methods. For instance, StarTrail precisely pinpointed the cancer-immune interface in a HER2+ breast cancer dataset, unveiled key cliff genes including a potential prognostic biomarker IGSF3, highlighting NK-, B-cell mediated immunity, and B cell receptor signaling pathways missed by all spatial variable gene methods attempted. StarTrail, filling important gaps in current literature, enables deeper insights into tissue spatial architecture.

genetics↗

Peripheral B Lymphocyte Serves as A Reservoir for The Persistently Covert Infection of Mandarinfish Siniperca chuatsi Ranavirus

Genus Ranavirus in family Iridoviridae is composed of large members with various genomic sizes and viral gene contents, infecting a variety of ectothermic vertebrates including reptile, amphibians and bony fish worldwide. Mandarinfish ranavirus (MRV) is a very distinctive member among genus Ranavirus. Persistently convert infection of MRV were previously observed in natural outbreak of MRV, but the underlying mechanism remains unclear. We here evidenced that mandarinfish peripheral B lymphocytes are implemented as viral reservoirs to maintain persistent and covert infection. When mandarinfish were infected with sublethal dosage of MRV under nonpermissive temperature (19 {o}C) and permissive temperature (26 {o}C), respectively, all fish in 19 {o}C group survived and entered persistent phase of infection characterized with very low viral load in white blood cell, whereas partial fish died of MRV infection in 26 {o}C group, and the survivals then initiated persistent status. Gradually raising temperature, vaccination and dexamethasone treatment can reactivate the quiescent MRV to replicate and result in partial mortality. The viral reservoir investigates showed that IgM+-labelled B lymphocytes but not CD3{Delta}+-labelled T lymphocytes and MRC-1+-labelled macrophages are target cells for the persistent infection of MRV. Moreover, the quiescent MRV could not be reactivated by heat-killed Escherichia coli, indicating a very different reactivation mechanism from that of other known rannaviral member. Collectively, we are the first to confirm the presence of B cell-dependent persistent and covert infection of ranavirus, and provide a new clue for better understanding the complex infection mechanism of vertebrate iridovirus, especially regarding ranavirus. IMPORTANCEViruses known as HIV, HBV and EBV etc. evade host immune clearance by establishing long-term even lifelong persistent or latent infection. In vertebrate iridovirus, FV3, the type species of genus Ranavirus was evidenced to establish persistent infection by using Xenopus peritoneal macrophages as reservoirs. MRV is a very distinctive ranavirus from FV3 with very different genomic content and host species. We here uncovered MRV establishes persistent and covert infection by using peripheral B lymphocytes as virus reservoirs. During persistent infection, very low copies of quiescent MRV were harbored in peripheral B lymphocytes. Water temperature stress, vaccination stimulation, and dexamethasone treatment can reactivate quiescent MRV to replicate in abundance via a non-TLR5-mediated manner, and results in recurrence of MRV disease. Our finding suggests the diversity and complexity of the pathogenic mechanisms among ranaviruses, and also has important scientific significance for in-depth understanding of the infection and immunity interaction of vertebrate iridoviruses.

microbiology↗

A human forebrain organoid model reveals the essential function of GTF2IRD1-TTR-ERK axis for the neurodevelopmental deficits of Williams Syndrome

Williams Syndrome (WS; OMIM#194050) is a rare disorder, which is caused by the microdeletion of one copy of 25-27 genes, and WS patients display diverse neuronal deficits. Although remarkable progresses have been achieved, the mechanisms for these distinct deficits are still largely unknown. Here, we have shown that neural progenitor cells (NPCs) in WS forebrain organoids display abnormal proliferation and differentiation capabilities, and synapse formation. Genes with altered expression are related to neuronal development and neurogenesis. Single cell RNA-seq (scRNA-seq) data analysis revealed 13 clusters in healthy control and WS organoids. WS organoids show an aberrant generation of excitatory neurons. Mechanistically, the expression of transthyretin (TTR) are remarkably decreased in WS forebrain organoids. We have found that GTF2IRD1 encoded by one WS associated gene GTF2IRD1 binds to TTR promoter regions and regulates the expression of TTR. In addition, exogenous TTR can activate ERK signaling and rescue neurogenic deficits of WS forebrain organoids. Gtf2ird1 deficient mice display similar neurodevelopmental deficits as observed in WS organoids. Collectively, our study reveals critical function of GTF2IRD1 in regulating neurodevelopment of WS forebrain organoids and mice through regulating TTR-ERK pathway.

neuroscience↗

High-efficiency PET Degradation with a Duo-enzyme System Immobilized on Magnetic Nanoparticles

The widespread consumption of PET worldwide has necessitated the search for environment-friendly methods for PET degradation and recycling. Among these methods, biodegradation stands out as a promising approach for recycling PET. The discovery of duo enzyme system PETase and MHETase in 2016, along with their engineered variants, has demonstrated significant potential in breaking down PET. Previous studies have also demonstrated that the activity of the enzyme PETase increases when it is immobilized on nanoparticles. To achieve highly efficient and complete PET depolymerization, we immobilized both FAST PETase and MHETase at a specific ratio on magnetic nanoparticles. This immobilization resulted in a 2.5-fold increase in product release compared with free enzymes. Additionally, we achieved reusability and enhanced stability of the enzyme bioconjugates.

bioengineering↗

Unlocking TAS2R14 activation through intricate multi-ligand binding networks

Bitter taste receptors, particularly TAS2R14, play central roles in discerning a wide array of bitter substances, ranging from dietary components to pharmaceutical agents1-3. In addition, TAS2R14 has broad expression in non-gustatory tissues, suggesting its important roles in selective physiological processes and therapeutic potential4. Here, we present cryo-electron microcopy structures of TAS2R14 in complex with flufenamic acid and aristolochic acid, coupling with G protein subtypes gustducin and Gi. Distinct from most known GPCRs, agonists of TAS2R14 bind to multiple intracellular pockets. We highlight the cholesterol molecules occupying an upper transmembrane site, typically the orthosteric pocket in other GPCRs, also binding in the entrance to an intracellular agonist binding pocket, suggesting an endogenous modulatory function5. The structural and mutagenesis analysis illuminate the receptors broad-spectrum ligand recognition and activation via intricate multiple ligand-binding sites. Furthermore, we unveil the structural configuration of gustducin and its interaction with TAS2R14, as well as the coupling mode of Gi1. This investigation should be instrumental in advancing our knowledge of the mechanisms underlying bitter taste recognition and response, with broader relevance to sensory biology and pharmacology.

biophysics↗