Biology subjects

Sun, M.

Publications and source records attributed to Sun, M..

At least 91 records · Page 5Linked to original sources

bioRxiv2024

Rapid radiation of a plant lineage sheds light on the assembly of dry valley biomes

Southwest China is characterized by high plateaus, large mountain systems, and deeply incised dry valleys formed by major rivers and their tributaries. Despite the considerable attention given to alpine plant radiations in this region, the timing and mode of the diversification of the numerous plant lineages in the dry valley habitat remains unknown. To address this knowledge gap, we investigate the macroevolution of Isodon (Lamiaceae), a lineage commonly distributed in the dry valleys in southwest China and wetter areas of Asia and Africa. We reconstructed a robust phylogeny encompassing nearly 90% of the approximately 140 extant Isodon species using transcriptome and genome-resequencing data. Our results suggest a rapid radiation of Isodon during the Pliocene that coincided with a habit shift from herbs to shrubs and a habitat shift from humid areas to dry valleys. The shrubby growth form likely acted as a preadaptation allowing for the movement of Isodon species into these valleys. Ecological analysis highlighted aridity and precipitation as key factors influencing the niche preferences of different growth forms and species richness of Isodon. Integrating our results with insights from tectonic movements in the Tibetan Plateau and adjacent regions, we infer that the interplay between topography and the evolution of the East Asian monsoon since the middle Miocene likely contributed to the formation of the dry valley biome in southwest China. This study enhances our understanding of evolutionary dynamics and ecological drivers shaping the distinctive flora of this region.

evolutionary biology↗

bioRxiv2024

Haplotype-resolved genomes and population genetics to analyze glandular secretory trichome formation mechanism in oregano

Oregano is an important economic plant which has valuable medicinal and aromatic properties. Oregano essential oil, containing carvacrol and thymol, is a preferred material to replace antibiotics in feed additives. Glandular secretory trichome (GST) density has positively correlated with the production of these compounds. Here, two haplotype-resolved genomes were assembled and annotated which contained 15 chromosomes with the total length of 606.75 and 612.74 Mb, respectively. Oregano had experienced two whole-genome duplications corresponding to the divergence [~]5.120/4.564 and [~]66.857/69.923 Mya, respectively. Many transcription factors and genes were found related to GSTs formation mechanism such as R2R3-MYB- and HD-ZIP IV-encoding genes. 2,669,410 SNPs, 569,093 InDels, 14,839 DUPs, 110 INVs, 3,976 TRANSs, and 1,426 CNVs were detected among two haplotype-resolved genomes. Two high density genetic linkage maps consisted of 15 LGs and spanned 2,279.28 and 2,322.83 cM, respectively. GADS, GABS, and GTS of F2 segregating populations showed obvious superparental dominance. One/one, one/one, and two/four QTLs for GADS, GABS, and GTS were independently mapped on two genetic maps, respectively. Five candidate genes showed extreme difference in two bulked segregant pools. Our study not only provides significant insight into the GSTs formation mechnism, but also will facilitate molecular breeding in oregano. One Sentence SummaryOregano essential oil is a preferred material to replace antibiotics which will use to study the glandular secretory trichome formation mechanism and analyze the source of essential oil.

genetics↗

bioRxiv2024

SAMP: Identifying Antimicrobial Peptides by an Ensemble Learning Model Based on Proportionalized Split Amino Acid Composition

AbstractIt is projected that 10 million deaths could be attributed to drug-resistant bacteria infections in 2050. To address this concern, identifying new-generation antibiotics is an effective way. Antimicrobial peptides (AMPs), a class of innate immune effectors, have received significant attention for their capacity to eliminate drug-resistant pathogens, including viruses, bacteria, and fungi. Recent years have witnessed widespread applications of computational methods especially machine learning (ML) and deep learning (DL) for discovering AMPs. However, existing methods only use features including compositional, physiochemical, and structural properties of peptides, which cannot fully capture sequence information from AMPs. Here, we present SAMP, an ensemble random projection (RP) based computational model that leverages a new type of features called Proportionalized Split Amino Acid Composition (PSAAC) in addition to conventional sequence-based features for AMP prediction. With this new feature set, SAMP captures the residue patterns like sorting signals at around both the N-terminus and the C-terminus, while also retaining the sequence order information from the middle peptide fragments. Benchmarking tests on different balanced and imbalanced datasets demonstrate that SAMP consistently outperforms existing state-of-the-art methods, such as iAMPpred and AMPScanner V2, in terms of accuracy, MCC, G-measure and F1-score. In addition, by leveraging an ensemble RP architecture, SAMP is scalable to processing large-scale AMP identification with further performance improvement, compared to those models without RP. To facilitate the use of SAMP, we have developed a Python package freely available at https://github.com/wan-mlab/SAMP.

bioinformatics↗

bioRxiv2024

Nuclear speckle rejuvenation alleviates proteinopathies at the expense of YAP1

Current treatments targeting individual protein quality control pathways have limited efficacy in alleviating proteinopathies, highlighting the prerequisite for a common druggable target capable of global proteostasis modulation. Building upon our prior research establishing nuclear speckles as pivotal membrane-less organelles for transcriptional control of proteostasis, we aim to alleviate proteinopathies through nuclear speckle rehabilitation. We identified pyrvinium pamoate as a nuclear speckle rehabilitator that enhances protein quality control gene expression and suppresses YAP1 transcriptional activity via decreasing the surface/interfacial tension of nuclear speckle condensates through interaction with the intrinsically disordered region of nuclear speckle scaffold protein SON. In pre-clinical models, nanomolar pyrvinium pamoate protected against retinal degeneration and tauopathy mainly by promoting autophagy and ubiquitin-proteasome activity in a SON-dependent manner without causing stress. Aberrant nuclear speckle morphology, reduced protein quality control and increased YAP1 activity were observed in human tauopathies. Our study provides proof-of-principle of targeting nuclear speckles to ameliorate proteinopathies.

cell biology↗

bioRxiv2024

Lytic bacteriophages interact with respiratory epithelial cells and induce the secretion of antiviral and proinflammatory cytokines

Phage therapy is a therapeutic approach to treat multidrug resistant infections that employs lytic bacteriophages (phages) to eliminate bacteria. Despite the abundant evidence for its success as an antimicrobial in Eastern Europe, there is scarce data regarding its effects on the human host. Here, we aimed to understand how lytic phages interact with cells of the airway epithelium, the tissue site that is colonized by bacterial biofilms in numerous chronic respiratory disorders. We determined that interactions between phages and epithelial cells depend on specific phage properties as well as physiochemical features of the microenvironment. Although poor at internalizing phages, the airway epithelium responds to phage exposure by changing its transcriptional profile and secreting antiviral and proinflammatory cytokines that correlate with specific phage families. Overall, our findings indicate that mammalian responses to phages are heterogenous and could potentially alter the way that respiratory local defenses aid in bacterial clearance during phage therapy. Thus, besides phage receptor specificity in a particular bacterial isolate, the criteria to select lytic phages for therapy should be expanded to include mammalian cell responses.

microbiology↗

bioRxiv2024

scMulan: a multitask generative pre-trained language model for single-cell analysis

Cells can be viewed as complex stories written by coordinated expression of genes. The success of AI large language models (LLMs) in mastering the human language inspired us to develop a large AI model scMulan with 368 million parameters to generate cell transcriptomics with designated attributes by learning the cell language. We defined a unified c-sentence to incorporate cell transcriptomics and meta-attributes, and pre-trained scMulan on the equivalence of 100 million human cells. Experiments showed that scMulan can generate designated pseudo transcriptomics, predict missing attributes of cells, reconstruct unobserved cells along functional gradients, and can help to identify driving regulators of cell fates. The generated data passed tests of current tools and can reflect the underlying biology.

bioinformatics↗

bioRxiv2024

Capturing Snapshots of Nucleosomal H2A K13/K15 Ubiquitination Mediated by the Monomeric E3 Ligase RNF168

AbstractsThe DNA damage repair regulatory protein RNF168, a monomeric RING-type E3 ligase, plays a crucial role in regulating cell fate and DNA repair by specific and efficient ubiquitination of the adjacent Lys13 and Lys15 sites at the H2A N-terminal tail. However, understanding how RNF168 coordinates with its cognate E2 enzyme UbcH5c to ubiquitinate H2AK13/15 site-specifically has long been hampered by the lack of high-resolution structures of RNF168 and UbcH5c[~]Ub in complex with nucleosomes. Here, we developed mechanism-based chemical trapping strategies and determined the cryo-EM structures of the RNF168/UbcH5c-Ub/NCP complex captured in transient H2AK13/15 monoubiquitination and adjacent dual-monoubiquitination reactions. Our structural analysis revealed that RNF168 stably binds to the nucleosomal H2A-H2B acidic patch through a basic helix with multiple interactions, which positions the UbcH5c active centre directly over the H2A N-terminus, providing a "helix-anchoring" mode for monomeric E3 ligase RNF168 on nucleosome in contrast to the "compass-binding" mode of dimeric E3 ligases. Furthermore, our chemically synthesized ubiquitinated histones have enabled the elucidation of the efficiency of Ub installation and the interplay between the initial and subsequent Ub modifications on the adjacent H2A K13 and K15 sites. Overall, our work not only provides structural snapshots of H2A K13/K15 site-specific monoubiquitination and adjacent dual-monoubiquitination, but also offers a near-atomic resolution structural framework for understanding how pathogenic mutations or physiological modifications affect the molecular function of RNF168 in H2A K13/15 ubiquitination.

biochemistry↗

bioRxiv2023

SntB triggers the antioxidant pathways to regulate development and aflatoxin biosynthesis in Aspergillus flavus

The epigenetic reader SntB was identified as an important transcriptional regulator of growth, development, and secondary metabolite synthesis in Aspergillus flavus. However, the underlying molecular mechanism is still unclear. In this study, sntB gene deletion ({Delta}sntB), complementary (Com-sntB), and HA tag fused to sntB (sntB-HA) strains were constructed by using the homologous recombination method, respectively. Our results revealed that deletion of sntB inhibited the processes of mycelia growth, conidial production, sclerotia formation, aflatoxin synthesis, and ability to colonize host, and the defective phenotype of knockout strain {Delta}sntB could be restored in its complementary strain Com-sntB. Chromatin immunoprecipitation sequencing (ChIP-seq) of sntB-HA and WT, and RNA sequencing (RNA-seq) of {Delta}sntB and WT strains revealed that SntB played key roles in oxidative stress response of A. flavus. The function of catC gene (encode a catalase) was further analyzed based on the integration results of ChIP-seq and RNA-seq. In {Delta}sntB strain, the relative expression level of catC was significantly higher than in WT strain, while a secretory lipase encoding gene (G4B84_008359) was down-regulated. Under the stress of oxidant menadione sodium bisulfite (MSB), the deletion of sntB obvious down-regulated the expression level of catC. After deletion of catC gene, the mycelia growth, conidial production, and sclerotia formation were inhibited, while ROS level and aflatoxin production were increased compared to the WT strain. Results also showed that the inhibition rate of MSB to {Delta}catC strain was significantly lower than that of WT group and AFB1 yield of the {Delta}catC strain was significantly decreased than that of WT strain under the stress of MSB. Our study revealed the potential machinery that SntB regulated fungal morphogenesis, mycotoxin anabolism, and fungal virulence through the axle of from SntB to fungal virulence and mycotoxin bio-synthesis, i.e. H3K36me3 modification-SntB-Peroxisomes-Lipid hydrolysis-fungal virulence and mycotoxin bio-synthesis. The results of this study shed light into the SntB mediated transcript regulation pathways of fungal mycotoxin anabolism and virulence, which provided potential strategy for control the contamination of A. flavus and its aflatoxins.

pharmacology and toxicology↗

bioRxiv2023

Single cell sequencing as a general variant interpretation assay

The human genome contains [~]70 million possible protein-altering variants, the vast majority of which are of uncertain clinical significance. Closing this gap is essential for accurate diagnosis of disease-causing variants and understanding their mechanisms of action. Towards this goal, we developed a pooled perturbation approach combining saturation mutagenesis with single cell RNA sequencing to map the effects of every single nucleotide variant in a gene. We sequenced [~]440,000 cells expressing variants in CDKN2A (p16INK4a), TP53, and SOD1, observing almost all possible protein-coding variants, with a mean of 61 cells per variant. Using single cell gene expression signatures, we show that each gene may contain multiple types of pathogenic variants that affect distinct downstream pathways. We demonstrate that single cell expression signatures outperform existing bulk experimental assays and computational models for predicting pathogenicity, and summarize both the utility and potential limitations of single cell sequencing as a general variant interpretation assay.

genomics↗

bioRxiv2023

Biological characteristics and metabolic phenotypes of different anastomosis groups of Rhizoctonia solani strains

Rhizoctonia solani is an important plant pathogen worldwide, and causes serious target spot disease in tobacco in the last five years. This research studied the biological characteristics of four different anastomosis groups (R. solani AG-3, R. solani AG-5, R. solani AG-6, R. solani AG-1-IB) of R. solani from tobacco, and analyzed the metabolic phenotype differences of these strains using metabolic phenotype technology. The results showed that the suitable temperature for mycelial growth of four anastomosis group strains were all from 20 to 30 {degrees}C, and for sclerotia formation were from 20 to 25 {degrees}C. Under different lighting conditions, R. solani AG-6 strains produced the most sclerotium, followed by R. solani AG-3, R. solani AG-5 and R. solani AG-1-IB. All strains had strong oligotrophic survivability, and can grow on water agar medium without any nitrutions. They exhibited three types of sclerotia distribution form, including dispersed type (R. solani AG-5 and R. solani AG-6), peripheral type (R. solani AG-1-IB), and central type (R. solani AG-3). They all presented different pathogenicities in tobacco leaves, with the most virulent was noted by R. solani AG-6, followed by R. solani AG-5 and AG-1-IB, finally was R. solani AG-3. R. solani AG-1-IB strains firstly present symbtom about inoculation. Metabolic fingerprints of four anastomosis groups were different to each other. R. solani AG-3, AG-6, AG-5 and AG-1-IB strains efficiently metabolized 88, 94, 71 and 92 carbon substrates, respectively. Nitrogen substrates of amino acids and peptides were the significant utilization patterns for R. solani AG-3. R. solani AG-3 and AG-6 showed a large range of adaptabilities and were still able to metabolize substrates in the presence of the osmolytes, including up to 8% sodium lactate. Four anastomosis groups all showed active metabolism in environments with pH values from 4 to 6 and exhibited decarboxylase activities. One-sentence summaryRhizoctonia solani strains from different anastomosis groups have a different adaptability to habitats.

microbiology↗

bioRxiv2023

Molecular and neuronal mechanisms governing sexually dimorphic prioritization of innate behaviors

Males and females display dimorphic innate behaviors and further prioritize them differently. How the sexually dimorphic behavioral prioritization is mediated is poorly understood. In Drosophila, around 60 pairs of pC1 neurons in males and 6 pairs in females control sexually dimorphic behaviors. We show that an increase of pC1 activity determines the sequential execution of behaviors such as sex, aggression, sleep, and feeding in a sex-specific way. We identify distinct subsets of pC1 neurons in both males and females that regulate different behaviors. We further discover diuretic hormone 44 (DH44) and acetylcholine (ACh) as co-transmitters in pC1 neurons. ACh promotes the execution of each behavior in both sexes, whereas DH44 functions in a sex-specific and activity-dependent manner to establish the sexually dimorphic behavioral outputs. These findings provide a framework for understanding the molecular and cellular mechanisms underlying sexually dimorphic prioritization of innate behaviors.

neuroscience↗

bioRxiv2023

rNMPID: a database for riboNucleoside Mono-Phosphates In DNA

MotivationRibonucleoside monophosphates (rNMPs) are the most abundant non-standard nucleotides embedded in genomic DNA. If the presence of rNMP in DNA cannot be controlled, it can lead to genome instability. The actual positive functions of rNMPs in DNA remain mainly unknown. Considering the association between rNMPs embedment and various diseases and cancer, the phenomenon of rNMPs embedment in DNA has become a prominent area of research in recent years. ResultsWe introduce the rNMPID database, which is the first database revealing rNMP-embedment characteristics, strand bias, and preferred incorporation patterns in the genomic DNA of samples from bacterial to human cells of different genetic backgrounds. The rNMPID database uses datasets generated by different rNMP-mapping techniques. It provides the researchers with a solid foundation to explore the features of rNMPs embedded in the genomic DNA of multiple sources, and their association with cellular functions, and, in future, disease. It also significantly benefits researchers in the fields of genetics and genomics who aim to integrate their studies with the rNMP-embedment data. AvailabilityrNMPID is freely accessible on the web at https://www.rnmpid.org. Contactxph6113@gmail.com or storici@gatech.edu

bioinformatics↗

bioRxiv2023

coRIC map: a framework for the exploration of multifaceted subcellular RNA-binding proteins

The ability of RNA-binding proteins (RBPs) to form complexes with other biomolecules underpins a broad range of functions and remarkable structural properties. Understanding the precise spatiotemporal dynamics of RBPs and their interacting partners in the steady state and upon perturbation is key to deciphering these aspects. Here, we present the coRIC (compartmentalized RNA Interactome Capture) map, an experimental resource and analytical pipeline to study the subcellular dynamics of RBPs through multimodal dataset integration and machine learning. Using this approach, we have generated an atlas comprising 1,768 RBPs distributed in a broad panel of subcellular compartments and delineated their intermolecular and intercompartmental relationships. We have also defined the hierarchy of RBP-containing complexes at multiple scales across the cell, uncovering previously unknown functions of multiple RBPs. Furthermore, we have investigated the changes in RBP complex composition and subcellular distribution in response to C9ORF72 amyotrophic lateral sclerosis/frontotemporal dementia dipeptide repeats and DNA damage stress. The coRIC map provides a valuable new approach for defining the roles of RBPs in homeostasis and disease.

cell biology↗

bioRxiv2023

Multi-region calcium imaging in freely behaving mice with ultra-compact head-mounted fluorescence microscopes

To investigate the circuit-level neural mechanisms of behavior, simultaneous imaging of neuronal activity in multiple cortical and subcortical regions is highly desired. Miniature head-mounted microscopes offer the capability of calcium imaging in freely behaving animals. However, implanting multiple microscopes on a mouse brain remains challenging due to space constraints and the cumbersome weight of equipment. Here, we present TINIscope, a Tightly Integrated Neuronal Imaging microscope optimized for electronic and opto-mechanical design. With its compact and lightweight design of 0.43 g, TINIscope enables unprecedented simultaneous imaging of behavior-relevant activity in up to four brain regions in mice. Proof-of-concept experiments with TINIscope recorded over 1000 neurons in four hippocampal subregions and revealed concurrent activity patterns spanning across these regions. Moreover, we explored potential multi-modal experimental designs by integrating additional modules for optogenetics, electrical stimulation or local field potential recordings. Overall, TINIscope represents a timely and indispensable tool for studying the brain-wide interregional coordination that underlies unrestrained behaviors.

neuroscience↗

bioRxiv2023

ATR promotes mTORC1 activation via de novo cholesterol synthesis in p16-low cancer cells

DNA damage and cellular metabolism exhibit a complex interplay characterized by bidirectional feedback mechanisms. Key mediators of the DNA damage response and cellular metabolic regulation include Ataxia Telangiectasia and Rad3-related protein (ATR) and the mechanistic Target of Rapamycin Complex 1 (mTORC1), respectively. Previous studies have established ATR as a regulatory upstream factor of mTORC1 during replication stress; however, the precise mechanisms by which mTORC1 is activated in this context remain poorly defined. Additionally, the activity of this signaling axis in unperturbed cells has not been extensively investigated. Here, we demonstrate that ATR promotes mTORC1 activity across various cellular models under basal conditions. This effect is particularly enhanced in cells following the loss of p16, which we have previously associated with hyperactivation of mTORC1 signaling and here found have increased ATR activity. Mechanistically, we found that ATR promotes de novo cholesterol synthesis and mTORC1 activation through the upregulation of lanosterol synthase (LSS), independently of both CHK1 and the TSC complex. Furthermore, the attenuation of mTORC1 activity resulting from ATR inhibition was rescued by supplementation with lanosterol or cholesterol in multiple cellular contexts. This restoration corresponded with enhanced localization of mTOR to the lysosome. Collectively, our findings demonstrate a novel connection linking ATR and mTORC1 signaling through the modulation of cholesterol metabolism.

cancer biology↗

bioRxiv2023

G6PD Maintains Redox Homeostasis and Biosynthesis in LKB1-Deficient KRAS-Driven Lung Cancer

Cancer cells depend on nicotinamide adenine dinucleotide phosphate (NADPH) to combat oxidative stress and support reductive biosynthesis. One major NAPDH production route is the oxidative pentose phosphate pathway (committed step: glucose-6-phosphate dehydrogenase, G6PD). Alternatives exist and can compensate in some tumors. Here, using genetically-engineered lung cancer model, we show that ablation of G6PD significantly suppresses KrasG12D/+;Lkb1-/-(KL) but not KrasG12D/+;p53-/- (KP) lung tumorigenesis. In vivo isotope tracing and metabolomics revealed that G6PD ablation significantly impaired NADPH generation, redox balance and de novo lipogenesis in KL but not KP lung tumors. Mechanistically, in KL tumors, G6PD ablation caused p53 activation that suppressed tumor growth. As tumor progressed, G6PD-deficient KL tumors increased an alternative NADPH source, serine-driven one carbon metabolism, rendering associated tumor-derived cell lines sensitive to serine/glycine depletion. Thus, oncogenic driver mutations determine lung cancer dependence on G6PD, whose targeting is a potential therapeutic strategy for tumors harboring KRAS and LKB1 co-mutations.

cancer biology↗

bioRxiv2023

Loss of the polarity protein Par3 promotes dendritic spine neoteny and enhances learning and memory

The Par3 polarity protein is critical for subcellular compartmentalization in different developmental processes. Variants of PARD3, which encodes PAR3, are associated with intelligence and neurodevelopmental disorders. However, the role of Par3 in glutamatergic synapse formation and cognitive functions in vivo remains unknown. Here, we show that forebrain conditional knockout of Par3 leads to an increase in long, thin dendritic spines without significantly impacting mushroom spines in vivo. In addition, we observed a decrease in the amplitude of miniature excitatory postsynaptic currents. Surprisingly, loss of Par3 in vivo enhances hippocampal- dependent spatial learning. Phosphoproteomic analysis revealed proteins regulating cytoskeletal dynamics are significantly dysregulated downstream of Par3. Mechanistically, we found Par3 deletion causes increased activation of the Rac1 pathway. Together, our data reveal an unexpected role for Par3 as a molecular gatekeeper in regulating the pool of immature dendritic spines, a rate-limiting step of learning and memory, through modulating Rac1 activation in vivo.

neuroscience↗

bioRxiv2023

Correlating stress reduction and eye movement patterns in a world famous Kyoto Japanese garden

Visual stimuli have been repeatedly shown to elicit significant non-visual responses. In a continuing effort to explore the unique effects of viewing a Japanese garden on the physiological and psychological metrics of stress, we gained access to the world famous Murin-an garden in Kyoto, Japan. This well-maintained observation garden was designed to be viewed while seated at a single vantage point to maximize the impact of the visual scene. As a control, we used a public garden on the campus of Kyoto University that was designed in a similar style. Sixteen college age students were asked to view both gardens while we monitored their pulse rates and tracked their eye movements. We used the POMS questionnaire to determine the effect of the garden viewing on the mood of the participants. We found that the Murin-an garden was more effective in decreasing pulse rate and improving mood than the University garden. The eye tracking data showed that during their Murin-an viewing the participants gaze ranged far more broadly across the visual field both the X-Y plane and in depth, and the speed with which the eyes moved from point-to-point was greater. Taken together, our data suggest that no one element in the garden was dominant in eliciting the changes in heart rate and mood. Rather, it was the breadth and rapidity of the shifts in gaze that drove the effects, a conclusion with implications for other interventions aimed stress reduction. SignificanceViews of nature and natural phenomena have a well-recognized calming effect on humans that has recognized therapeutic value in both medical and psychological settings. Our work explores the source of this effect by having participants view Murin-an, a world-famous Japanese style garden. Using both psychological and physiological measures, we confirm and extend earlier findings showing that a well constructed garden can effectively lower heart rate and improve mood within minutes. We also find, by analogy with eye movement desensitization and reprograming (EMDR), that it is participants rapidly shifting gaze rather than a single specific visual object is the most likely source of the calming effect.

neuroscience↗