Biology subjects

Jin, Y.

Publications and source records attributed to Jin, Y..

At least 73 records · Page 4Linked to original sources

bioRxiv2025

Discover the Maze-like Pathway for Glabridin Biosynthesis

Tailoring enzymes diversify plant metabolite scaffolds through complex, context-dependent modifications, generating maze-like biosynthetic networks that complicate metabolic pathway reconstruction. Here, we systematically deconstructed and reconstructed the biosynthetic network of glabridin, a valuable skin-whitening isoflavone from Glycyrrhiza. By integrating metabolic pathway mining with genome and 183 transcriptomes, we identified four functional routes among sixteen theoretical possibilities and uncovered a previously uncharacterized, ladder-like multi-route tailoring network. Reconstruction of such architecture in yeast revealed metabolic redundancy and interconnectivity confer unexpected robustness, enabling higher production efficiencies compared to a single-route design. Further modular engineering enabled the de novo biosynthesis of glabridin in yeast. Our work establishes a framework for reconstructing metabolic mazes and demonstrates that multi-route architectures can be harnessed to enhance the robustness and productivity of cell factories.

synthetic biology↗

bioRxiv2025

A Fully Defined Yeast iVT tRNA Translation Platform and the Synergistic Role of eIF5A and Mg2+

Cell-free translation platforms enable genetic-code engineering but typically rely on native transfer RNAs (tRNAs). Here we reconstitute Saccharomyces cerevisiae translation using a fully synthetic set of 21 in vitro-transcribed tRNAs--one isoacceptor per canonical amino acid plus the initiator--that collectively decode all 61 sense codons. After individual aminoacylation, this minimal pool supports peptide synthesis in a fully recombinant yeast cell-free translation system at yields comparable to native tRNAs. Translation of long open reading frames stalls without supplementation; adding either eukaryotic initiation factor 5A (eIF5A) or elevated Mg2+ restores activity, and together they increase Nano luciferase (NanoLuc) output by approximately fivefold. Alanine scanning implicates basic residues R27 and R87 in eIF5A, rather than the hypusine side chain, as the principal contributors to P-site tRNA stabilization. Higher Mg2+ alone accelerates elongation but increases UAG/UGA readthrough to [~]15%, revealing a tunable speed-fidelity trade-off with unmodified tRNAs. Installing t6A37 or m1G37 on selected synthetic tRNAs further improves processivity. This minimal, programmable yeast platform enables systematic dissection of tRNA-modification functions and provides a practical route to genetic-code engineering.

molecular biology↗

bioRxiv2025

Ancient DNA Reveals Hominoid Evolution: Intermediate DNA Sequences and Advances in Molecular Paleontology

AbstractFossils and ancient crude pottery vessels function as physical "DNA containers," preserving oriDNA (original, in situ DNA) and accumulating eDNA (environmental DNA) over time. Ancient DNA (aDNA) serves as molecular fossils, chronicling evolutionaryhistory. Using "nano-affinitybead technology", we extracted and sequenced DNAfrom Lycoptera fossils in the Jehol region and a "round-bellied jar (Jar)" from the Erlitou period in Guangwu Town, yielding 236,545 primate sequences from the fossils and 86,908 from the pottery. We observed that the AFF value of DNA sequences negatively corre lates with species divergence time1, offering a quantitative measure of DNA preservation and host divergence. Some fragments distinct from modern genomic sequences, termed "intermediate DNAsequences" (IDS), have been identified. Many IDS exhibit an upper age limit, preserving characteristics of the last common ancestor (LCA) of the Hominidae and offering molecular insights into "Darwins puzzle". Among IDS, the SRRA subtype (Sequence Reversal and Rearrangement), identified in mRNA-coding exonic sequences, arises from the incorporation of a complementary antisense strand upstream of the sense strand, either adjacent to it or separated bya sequence interval. This introduces a novel post-transcriptional regulatory mechanism at the mRNA level, driven by SRRA, which presets hairpin structures and Indels in the UTR or CDS of exonic sequences, modulating gene variation. We propose: "SRRAs played a critical trial-and-error role in early Hominidae evolution, facilitating adaptive genomic changes, with some SRRA sequences later excised from exons", positioning SRRAas an evolutionary "genetic switch". Additionally, seven species -specific fragments (SSFs) of non-human primates (NHPs) linked to Asian Homo erectus were identified in the fossils, and pottery DNA reveale d sequences from tropical species (e.g., zebrass, oil palms), providing evidence of climate-driven local extinction and supporting paleo-ecological and paleo-environmental reconstruction. This method of analyzing aDNA from non-skeletal materials opens new avenues in paleontology, archaeology, and geology, guiding the tracing of ancient migration patterns and fossil searches. DNAfragments preserved within "DNA containers " exhibit an "old-few, new-many" turnover pattern, with many aDNA fragments displaying non-deamination. This evidence challenges prevailing perspectives, the authenticity criteria for aDNA, and the capabilities and scope of the traditional research method, necessitating a thorough reevaluation of the relevant knowledge framework. Furthermore, this study opens new opportunities for frontier research.

paleontology↗

bioRxiv2025

An intercellular metabolic relay for brain sparingin Drosophila

Brain sparing protects growth of the central nervous system (CNS) at the expense of other developing organs during nutrient restriction. This survival strategy is conserved from Drosophila to mammals but little is known about its underlying metabolic mechanisms. Here, we show that CNS uptake and catabolism of circulating glutamine is essential for neural stem cell proliferation during brain sparing but not normal brain development. Glutamine is imported into perineurial glia of the blood-brain-barrier, which upregulate glutaminase (Gls) and vesicular glutamate transporter 1 (VGlut1) to promote glutaminolysis and glutamate secretion. Neural stem cells then import released glutamate via excitatory amino acid transporter 1 (Eaat1) and maintain it at homeostatic levels via glutamine synthetase 1 (Gs1). Glutamine nitrogen contributes surprisingly little to newly synthesized DNA or protein in neural stem cells but its carbon fuels the oxidative tricarboxylic acid cycle. These findings identify an intercellular metabolic relay specifically required to sustain the proliferation of neural stem cells during brain sparing.

developmental biology↗

bioRxiv2025

Simultaneous measurement of intrinsic promoter and enhancer potential reveals principles of functional duality and regulatory reciprocity

Accumulating evidence indicates that both promoters and enhancers are capable of exerting promoter and enhancer functions; however, the relationship between these two activities within individual elements and the determinants of this dual functionality remain poorly understood. We developed a massively parallel dual reporter assay that enables simultaneous assessment of the intrinsic promoter and enhancer potential exerted by the same sequence. Parallel quantification for thousands of elements reveals that canonical human promoters and enhancers can act as both promoters and enhancers under the same contexts, and that promoter activity may be necessary but not sufficient for enhancer function. Perturbations to element transcription factor binding motifs lead to disruptions in both activities, implicating a shared syntax for the two regulatory functions. Combinations of elements with different minimal promoters reveal reciprocal activity modulation, which, together with a strong correlation between promoter and enhancer functions, imply a bidirectional feedback loop to sustain environments of high transcriptional activity. Finally, we validate this reciprocity and correlation in situ using CRISPR activation at the human {beta}-globin locus. Our approach reveals that the functional convergence between promoters and enhancers arises from a shared regulatory logic and sequence syntax, advancing a unified model for regulatory element biology.

genomics↗

bioRxiv2025

IGF1R-Targeted Delivery of a Bridged Nucleic Acid Oligonucleotide-Peptide Conjugate for MicroRNA 21 Inhibition in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC), defined by the absence of ER, PR, and Her2, impacts over 46,000 U.S. women annually, disproportionately affecting minority ethnic groups and individuals with BRCA1 mutations. Despite advancements such as PARP inhibitors, TNBC remains highly aggressive, with frequent recurrences and a 50% mortality rate within four years, underscoring the urgent need for more effective targeted therapies. MicroRNAs (miRNAs) represent a novel therapeutic approach. In TNBC, overexpressed miR-21 drives tumor progression, immune evasion, treatment resistance, and metastasis. Targeted miR-21 inhibition could curb these effects while minimizing harm to normal cells. We developed a peptide-conjugated miR-21 inhibitor targeting TNBC cells via the overexpressed IGF1 receptor (IGF1R), associated with poor prognosis. Using aminomethyl-bridged nucleic acid (BNA) chemistry, a serum-stable, low-toxicity anti-miR-21 RNA analog was created and tested for its effects on TNBC cell proliferation, apoptosis, tumor suppressor expression, and immune checkpoint regulation. Conjugation to an IGF1 peptide analog improved delivery, demonstrating tumor-specific biodistribution, efficacy, and safety in TNBC-bearing mice. The miR-21 inhibitor-peptide conjugate reduced proliferation, induced apoptosis, elevated tumor suppressors, and suppressed immune checkpoints in TNBC cell lines. In vivo, it targeted tumors, halted growth, and showed no liver or kidney toxicity, supporting its potential as a targeted, low-toxicity TNBC therapy.

cancer biology↗

bioRxiv2025

Chromatin remodeling integrates vertebrate body axis elongation and cell fate determination

The effective elongation of the vertebrate body axis depends on the precise coordination of cell movements and cell fate determination within the posterior tailbud region. However, the specific biological determinant that integrates these cellular processes during vertebrate tail bud elongation has remained unclear. Here, we demonstrate that the spatiotemporal heterogeneity of chromatin condensation states governs both cell fate and cell motility within the mesodermal progenitor zone (MPZ) and the presomitic mesoderm (PSM) during zebrafish tail bud elongation. By integrating biological experiments with computational modeling, we reveal that nuclear volume heterogeneity, mediated by chromatin remodeling, acts as an active driver of collective cell migration. Reducing chromatin condensation heterogeneity in the MPZ through modulation of chromatin modifications impairs collective cell movements and delays tailbud elongation. Single cell ATAC-seq and RNA-seq analyses reveal that global chromatin accessibility heterogeneity and region-specific chromatin remodeling differences in the PSM and MPZ are functionally associated with gene expression pathways involving in cell lineage specification. These findings establish a molecular connection between cell fate determination and tissue-scale cellular dynamics. Collectively, our findings unveil a unifying framework for understanding the coordination of cell fate determination and large-scale cellular movements during tissue morphogenesis.

developmental biology↗

bioRxiv2025

NADPH oxidase inhibitor enhances brain resilience in Alzheimer's disease by reducing tauopathy and neuroinflammation

Alzheimers disease associates closely with activation of NADPH oxidase (Nox) isozymes. We identified that CRB-2131, a novel oxadiazole derivative, potently suppresses Nox isozymes. It inhibits reactive oxygen species production (ROS) by hippocampal neuronal and microglial cells and reduces microglial activation. Prophylactic (starting at 3.5 months of age) and therapeutic (starting at 6 months of age) oral administration with CRB-2131 for 10 weeks in 5XFAD mice reduced hippocampal superoxide levels, lipid peroxidation, Tau phosphorylation, and neuroinflammation. Prophylactic and therapeutic CRB-2131 treatment of 5XFAD mice restored their impaired cognition as shown by the novel-object recognition, Y-maze, and Morris water-maze tests. CRB-2131 treatment increased mature neurons, reduced apoptotic mature neurons, and elevated immature neurons in the hippocampus. Positron-emission tomography/computed-tomography imaging confirmed that CRB-2131 stimulated neuronal regeneration. CRB-2131 suppresses brain oxidation, tauopathy, and neuroinflammation, thereby preventing mature neuron death and promoting neuron regeneration. Ultimately, this fosters a resilient brain and protects cognition.

neuroscience↗

bioRxiv2025

Lifespan Mapping of EEG Source Spectral Dynamics with Xi-AlphaNET

We introduce{xi} - Net, a mesoscale generative model of cortical activity that models the EEG aperiodic ({xi}) and -rhythm () components via Hida-Matern processes constrained by anatomical connectivity and interareal delays. This framework integrates fractional differential equations (modeling damping/resonance), decomposition of Spectral Granger Causality, and lifespan quantification. Bayesian inversion of the model, on cross-spectral rsEEG data from 1,965 participants aged 5-100 years (HarMNqEEG dataset), allows us to estimate cortical activity and effective connectivity patterns at 8,003-voxel resolution.{xi} processes showed extended cortical networks, with occurrence probability increasing with age but amplitude peaking midlife (inverted-U trajectory). processes exhibited a localization in the posterior areas of the cortex and two specialized networks (parieto-occipital, sensorimotor), with increasing localization probability and peak amplitude/frequency showing age-linked inverted-U trajectory. The model uniquely estimates global conduction delays, which are negatively correlated with frequency and independent myelin concentration profiles, mechanistically linking neural propagation times to regulation.

neuroscience↗

bioRxiv2025

Structural and Functional Insights into GGCX-FIX Interaction: Implications for Vitamin K-Dependent Bleeding Disorders

Gamma-carboxylation, catalyzed by {gamma}-glutamyl carboxylase (GGCX), is a critical post-translational modification essential for the biological activity of vitamin K-dependent proteins (VKDPs). Mutations in GGCX, depending on their specific location, result in vitamin K-dependent coagulation factor deficiency type 1 (VKCFD1), which encompasses a broad spectrum of clinical manifestations ranging from mild to severe, including bleeding disorders, osteoporosis, and vascular calcification. The limited knowledge of GGCXs structure and functional regions hinders our understanding of the consequences of GGCX mutations and the treatment for VKCFD1. This study aimed to identify key functional regions of GGCX and their interactions with VKDPs to better elucidate the molecular mechanisms underlying these diverse clinical symptoms. Using AlphaFold 3 and molecular dynamics simulations, we developed a complex binding model of GGCX, FIX, and reduced vitamin K, which revealed critical regions and residues involved in their interaction. Site-directed mutagenesis and cell-based assays further validated the model, confirming that multisite and regional cooperative binding of FIX to GGCX plays a key role in modulating {gamma}-carboxylation efficiency. Additionally, novel residues (I296, M303, M401, M402) were identified as essential for GGCXs dual enzymatic activities: carboxylation and vitamin K epoxidation. We further demonstrated that the spatial proximity of these active sites supports the hypothesis that GGCXs carboxylation and vitamin K epoxidation centers are interconnected, ensuring the efficient coupling of these processes. Our GGCX-FIX binding and carboxylation model aligns with known pathogenic GGCX mutations, providing valuable insights into the molecular basis of coagulation disorders caused by GGCX mutants.

pathology↗

bioRxiv2025

Context-specific interaction of the lipid regulator DIP-2 with phospholipid synthesis in axon regeneration and maintenance.

Neurons maintain their morphology over prolonged periods of adult life with limited regeneration after injury. C. elegans DIP-2 is a conserved regulator of lipid metabolism that affects axon maintenance and regeneration after injury. Here, we investigated genetic interactions of dip-2 with mutants in genes involved in lipid biosynthesis and identified roles of phospholipids in axon regrowth and maintenance. CEPT-2 and EPT-1 are enzymes catalyzing the final steps in the de novo phospholipid synthesis (Kennedy) pathway. Loss of function mutants of cept-2 or ept-1 show reduced axon regrowth and failure to maintain axon morphology. We demonstrate that CEPT-2 is cell-autonomously required to prevent age-related axonal defects. Interestingly, loss of function in dip-2 led to suppression of the axon regrowth phenotype observed in either cept-2 or ept-2 mutants, suggesting that DIP-2 acts to counterbalance phospholipid synthesis. Our findings reveal the genetic regulation of lipid metabolism to be critical for axon maintenance under injury and during aging. Article SummaryLittle is known about how adult neurons live long with limited regenerative capacity. This study investigates the role of lipid metabolism in sustaining neuronal health in C. elegans. Mutating phospholipid synthetic genes impairs axon regrowth after injury. Lack of DIP-2, a lipid regulator, restores regrowth, suggesting DIP-2 counterbalances phospholipid synthesis. Moreover, neuronal phospholipid synthesis is essential for preventing age-dependent axonal defects. These findings reveal phospholipid biosynthesis is key to axon integrity during aging and injury. As lipid metabolism is implicated in neurological disorders, this study serves as an entry point into investigating neuronal lipid biology under various conditions.

neuroscience↗

bioRxiv2025

Dietary quorum quenching AHL lactonase impairs the adaptation of commensal bacterium to host innate immunity

Quorum sensing (QS) is the communication system of bacteria that depends on QS signals. Quorum quenching (QQ) enzymes degrade QS signals and are promising alternatives of antibiotics to treat bacterial infections. Here, we found that dietary QQ N-acyl homoserine (AHL) lactonase led to microbiota dysbiosis in zebrafish, with reduction of Aeromonas and enrichment of Plesiomonas. Through gnotobiotic zebrafish colonized with a minimal microbiota, we found that QQ-mediated microbial alteration relies on host Myd88 signaling and neutrophil elastase. Mechanistically, quorum quenching increased the susceptibility of commensal Aeromonas to host neutrophil elastase by impairing bacterial lateral flagellar system, leading to reduced colonization of Aeromonas and subsequent enrichment of Plesiomonas due to ecological competition of the two species. Together, we found that dietary QQ lactonase led to microbiota alteration by impairing the adaptation of commensal Aeromonas to host innate immunity, which provided novel insight in the role of quorum sensing in host-microbiota interaction.

microbiology↗

bioRxiv2025

MetaLigand: A database for predicting non-peptide ligand mediated cell-cell communication

Non-peptide ligands (NPLs), including lipids, amino acids, carbohydrates, and non-peptide neurotransmitters and hormones, play a critical role in ligand-receptor-mediated cell-cell communication, driving diverse physiological and pathological processes. To facilitate the study of NPL-dependent intercellular interactions, we introduce MetaLigand, an R-based and web-accessible tool designed to infer NPL production and predict NPL-receptor interactions using transcriptomic data. MetaLigand compiles data for 233 NPLs, including their biosynthetic enzymes, transporter genes, and receptor genes, through a combination of automated pipelines and manual curation from comprehensive databases. The tool integrates both de novo and salvage synthesis pathways, incorporating multiple biosynthetic steps and transport mechanisms to improve prediction accuracy. Comparisons with existing tools demonstrate MetaLigands superior ability to account for complex biogenesis pathways and model NPL abundance across diverse tissues and cell types. Furthermore, analysis of single-nucleus RNA-seq datasets from age-related macular degeneration samples revealed that distinct retinal cell types exhibit unique NPL profiles and participate in specific NPL-mediated pathological cell-cell interactions. Finally, MetaLigand supports single-cell RNA sequencing (scRNA-seq) and spatial transcriptomics data, enabling the visualization of predicted NPL production levels and heterogeneity at single-cell resolution.

bioinformatics↗

bioRxiv2024

A Locus Control Region Generates Distinct Active Placental Lactogen And Inactive Growth Hormone Gene Domains In Term Placenta That Are Disrupted With Obesity

A Placental villi include an outer layer of syncytiotrophoblasts (STBs) and an inner layer of cytotrophoblasts (CTBs) that fuse to generate STBs in pregnancy. While activation of the single locus containing the human (h) placental lactogen (hPL) genes (hPL-A/CSH1 and hPL-B/CSH2) begins in the CTBs, their expression in STBs requires further epigenetic modifications as well as interactions between locus control region (LCR) and gene regulatory sequences. No transcription factor that limits or facilitates hPL LCR/gene interactions for locus activation is reported but the paternally-expressed gene 3 (PEG3/PW1) transcription factor is a candidate. PEG3 is expressed by villous CTBs but not STBs, and putative PEG3 sites were identified in the hPL LCR and promoter sequences. Furthermore, dysregulation of both hPL and PEG3 gene expression have been linked to peripartum depression. Using CTB-like JEG-3 cells, we show PEG3 binding to hypersensitive sites (HS III-V) within the LCR, and that hPL transcript levels increase with PEG-3 knockdown. In term placenta, PEG3 binding at placenta-specific HS IV was increased with maternal obesity, where a decrease in hPL RNA levels is seen, while PEG3 binding was reduced in women with obesity who develop insulin-treated gestational diabetes mellitus (O/GDM+Ins), where increased hPL gene expression is observed. Chromatin conformation capture revealed distinct hPL gene domain interactions that are modified with maternal obesity but largely reversed in O/GDM+Ins, correlating with PEG3 binding. Thus, decreased PEG3 binding may be required for hPL domain generation and expression during CTB to STB transition.

molecular biology↗

bioRxiv2024

deepBlastoid: A Deep Learning-Based High-Throughput Classifier for Human Blastoids Using Brightfield Images with Confidence Assessment

Recent advances in human blastoids have opened new avenues for modeling early human development and implantation. Human blastoids can be generated in large numbers, making them suitable for high-throughput screening, which often involves analyzing vast numbers of images. However, automated methods for evaluating and characterizing blastoid morphology are still underdeveloped. We developed a deep-learning model capable of recognizing and classifying blastoid brightfield images into five distinct quality categories. The model processes 53.2 images per second with an average accuracy of 87%, without signs of overfitting or batch eHects. By integrating a Confidence Rate (CR) metric, the accuracy was further improved to 97%, with low-CR images flagged for human review. In a comparison with human experts, the model matched their accuracy while significantly outperforming them in throughput. We demonstrate the value of the model in two real-world applications: (1) systematic assessment of the eHect of lysophosphatidic acid (LPA) concentration on blastoid formation, and (2) evaluating the impact of dimethyl sulfoxide (DMSO) on blastoids for drug screening. In the applications involving over 10,000 images, the model identified significant eHects of LPA and DMSO, which may have been overlooked in manual assessments. The deepBlastoid model is publicly available and researchers can train their own model according to their imaging conditions and blastoid culture protocol. deepBlastoid thus oHers a precise, automated approach for blastoid classification, with significant potential for advancing mechanism research, drug screening, and clinical in vitro fertilization (IVF) applications.

developmental biology↗

bioRxiv2024

NOLC1 Suppresses Immuno-chemotherapy by Inhibiting p53-mediated Ferroptosis in Gastric Cancer

Gastric cancer (GC) is one of the most malignant cancers, and cisplatin (Cis)-based chemotherapy remains the main clinical treatment for GC. However, Cis resistance often occurs, largely limiting its therapeutic efficacy in tumors. Therefore, a better understanding of the drug resistance mechanism could reveal new approaches for improving GC treatment efficacy. Here, we define the integrative role of nucleolar and coiled-body phosphoprotein 1 (NOLC1), a molecular chaperone that is significantly upregulated in GC tissues and Cis-resistant GC cells. Knocking down NOLC1 increased GC sensitivity to Cis by regulating ferroptosis. Mechanistically, NOLC1 binds to the p53 DNA binding domain (DBD), decreasing p53 nuclear accumulation stimulated by Cis and suppressing p53 transcriptional functions. Then, the p53-mediated ferroptosis is suppressed. Furthermore, the silence of NOLC1 promoted ferroptosis-induced immunogenic cell death (ICD) and reprogrammed the immunosuppressive tumor microenvironment, thereby increasing sensitivity to anti-programmed cell death-1 (PD-1) therapy plus Cis. The combination of anti-PD-1 plus Cis effectively inhibited GC growth without significant side effects. In summary, our findings reveal that targeting NOLC1 may be a novel therapeutic strategy for GC and may increase the efficacy of chemotherapy combined with immune checkpoint inhibitor (ICI) therapy.

cancer biology↗

bioRxiv2024

Species-specific circular RNA circDS-1 enhances adaptive evolution in Talaromyces marneffei through regulation of dimorphic transition and virulence

Thermal adaptability is a crucial characteristic for mammalian pathogenic fungi that originally inhabit natural ecosystems. Thermally dimorphic fungi have evolved a unique ability to respond to host body temperature by shifting from mycelium to yeast. The high similarity of protein-coding genes between these fungi and their relatives suggests the indispensable but often overlooked roles of non-coding elements in fungal thermal adaptation. Here, we systematically delineated the landscape of full-length circRNAs in both mycelial and yeast conditions of Talaromyces marneffei, a typical thermally dimorphic fungus causing fatal Talaromycosis, by optimizing an integrative pipeline for circRNA detection utilizing next- and third-generation sequencing. We found T. marneffei circRNA demonstrated features such as shorter length, lower abundance, and circularization-biased splicing. We then identified and validated that circDS-1, independent of its parental gene, promotes the hyphae-to-yeast transition, maintains yeast morphology, and is involved in virulence regulation. Further analysis and experiments among Talaromyces confirmed that the generation of circDS-1 is driven by a T. marneffei-specific region in the flanking intron of circDS-1. Together, our findings not only provide fresh insights into the role of circRNA in fungal thermal adaptation but also reveal a novel molecular mechanism for the adaptive evolution of functional circRNAs derived from intronic mutations. Author SummaryIt is an essential characteristic for human pathogens to survive under human body temperature, which is obviously higher than environmental temperature. The morphology transformation between mycelia and yeasts of thermally dimorphic fungi are tightly associated with temperature. The limited divergences of protein-coding genes among their closest relatives are not able to explain these fungi thermal dimorphism. CircRNAs are non-coding RNAs that distribute ubiquitously across eukaryotes. However, lower eukaryotes have been relatively neglected in circRNA research, either from the biological function level or from the evolutionary level. Our study focused on the typical thermally dimorphic fungus, Talaromyces marneffei. We combined next-generation and third-generation sequencing technologies to map the full-length circRNA profile in both the saprophytic mycelial and pathogenic yeast forms of T. marneffei to identify functional circRNAs. Gene manipulation experiments were performed to evaluate the functional impact of the target circRNA circDS-1. We uncovered unique characteristics of T. marneffei circRNAs, such as shorter lengths, reduced abundance, and a preference for circularization-biased splicing events. CircDS-1, which functions independently from its host gene to promote the transition from hyphae to yeast form, maintain yeast morphology, and modulate virulence. Our study not only offers fresh perspectives on the role of circRNAs in fungal thermal adaptation, but also enhances our understanding of the adaptive evolution of pathogenic fungi as they transform from environmental to host environments.

microbiology↗

bioRxiv2024

Differential Ubiquitination of Host Proteins in Response to IPNV and ISAV viruses in Atlantic salmon

Viral diseases remain a major barrier to the sustainable production of farmed fish, primarily attributable to the absence of effective prevention and treatment options. Understanding host-pathogen interactions can guide the development of vaccines, antiviral therapies, or gene editing strategies. Ubiquitination is a key cell signalling molecule, known to regulate many aspects of immune functions but currently understudied in fish. This study leverages ubiquitin-enriched mass spectroscopy complemented with RNA sequencing to characterize the role of ubiquitination in response to infection. A challenge experiment was conducted by infecting Atlantic salmon head kidney (SHK-1) cells with Infectious salmon anaemia virus (ISAV) and Infectious pancreatic necrosis virus (IPNV). At 24- and 48 hours post-infection dramatic changes were observed in the global ubiquitination state of host proteins. Many post-translational modifying proteins increased in abundance upon ISAV infection, whilst IPNV infection resulted in a reduction in abundance of many of these proteins. Transcriptomics showed a delay in the activation of the antiviral response to ISAV infection, with major upregulation of genes associated with immune pathways only at 48h. On the contrary, IPNV infection resulted in upregulation of classic innate immune response genes at both timepoints. Clear activation of Rig-like receptor pathways is demonstrated in both infections, in addition to upregulation of both conserved and novel antiviral TRIM E3 ubiquitin ligate genes. Network analysis identified clusters of immune genes and putatively regulatory proteins showing differential ubiquitination upon viral infection. This study highlights the importance of post-translational control of the host innate immune response to viruses in Atlantic salmon. Clear differences in ubiquitination between two viruses indicate either virus-specific post-translational regulation or viral antagonism of the immune response. Additionally, the ubiquitination of various proteins was linked to the regulation of innate immune pathways, suggesting a direct role of ubiquitination in the regulation of antiviral responses. AUTHOR SUMMARYUbiquitination is a main cellular regulatory mechanism in all animal species, controlling the activity of many proteins within the cell. The role of ubiquitination in the regulation of immunity is well-established, and several direct interactions with viruses have been described, either as part of a strategy of the host to fight the infection or as a viral mechanism to evade the host immune response. In aquaculture, viral diseases currently represent the most important threat to the sustainability of the industry. However, very little is known about the interplay between ubiquitination and viral pathogens in fish species. In our study, we have assessed the ubiquitination response of Atlantic salmon to two production-relevant viruses, Infectious salmon anaemia virus (ISAV) and Infectious pancreatic necrosis virus (IPNV). We found remarkable differences in the ubiquitination profiles between the two infections, suggesting a key role of ubiquitination on the early immune response. We also discovered an association between the ubiquitination of certain regulatory proteins and the activation of antiviral pathways. This information could help develop new strategies to tackle viral diseases in aquaculture, such as the development of more effective vaccines or antiviral therapies, or inform gene editing efforts to generate disease resistant fish.

molecular biology↗