SnapShot: N-Glycosylation Processing Pathways across Kingdoms.

Post-translational modification of proteins with carbohydrates shapes their localization and function. This SnapShot presents the core pathways from different organisms that install these complex and highly variable structures.

Arabinosylation of cell wall extensin is required for the directional response to salinity in roots.

Soil salinity is a major contributor to crop yield losses. To improve our understanding of root responses to salinity, we developed and exploited a real-time salt-induced tilting assay. This assay follows root growth upon both gravitropic and salt challenges, revealing that root bending upon tilting is modulated by Na+ ions, but not by osmotic stress. Next, we measured this salt-specific response in 345 natural Arabidopsis (Arabidopsis thaliana) accessions and discovered a genetic locus, encoding the cell wall-modifying enzyme EXTENSIN ARABINOSE DEFICIENT TRANSFERASE (ExAD) that is associated with root bending in the presence of NaCl (hereafter salt). Extensins are a class of structural cell wall glycoproteins known as hydroxyproline (Hyp)-rich glycoproteins, which are posttranslationally modified by O-glycosylation, mostly involving Hyp-arabinosylation. We show that salt-induced ExAD-dependent Hyp-arabinosylation influences root bending responses and cell wall thickness. Roots of exad1 mutant seedlings, which lack Hyp-arabinosylation of extensin, displayed increased thickness of root epidermal cell walls and greater cell wall porosity. They also showed altered gravitropic root bending in salt conditions and a reduced salt-avoidance response. Our results suggest that extensin modification via Hyp-arabinosylation is a unique salt-specific cellular process required for the directional response of roots exposed to salinity.

Reconstruction of single-cell lineage trajectories and identification of diversity in fates during the epithelial-to-mesenchymal transition.

Exploring the complexity of the epithelial-to-mesenchymal transition (EMT) unveils a diversity of potential cell fates; however, the exact timing and mechanisms by which early cell states diverge into distinct EMT trajectories remain unclear. Studying these EMT trajectories through single-cell RNA sequencing is challenging due to the necessity of sacrificing cells for each measurement. In this study, we employed optimal-transport analysis to reconstruct the past trajectories of different cell fates during TGF-beta-induced EMT in the MCF10A cell line. Our analysis revealed three distinct trajectories leading to low EMT, partial EMT, and high EMT states. Cells along the partial EMT trajectory showed substantial variations in the EMT signature and exhibited pronounced stemness. Throughout this EMT trajectory, we observed a consistent downregulation of the EED and EZH2 genes. This finding was validated by recent inhibitor screens of EMT regulators and CRISPR screen studies. Moreover, we applied our analysis of early-phase differential gene expression to gene sets associated with stemness and proliferation, pinpointing ITGB4, LAMA3, and LAMB3 as genes differentially expressed in the initial stages of the partial versus high EMT trajectories. We also found that CENPF, CKS1B, and MKI67 showed significant upregulation in the high EMT trajectory. While the first group of genes aligns with findings from previous studies, our work uniquely pinpoints the precise timing of these upregulations. Finally, the identification of the latter group of genes sheds light on potential cell cycle targets for modulating EMT trajectories.

A phytoplasma effector destabilizes chloroplastic glutamine synthetase inducing chlorotic leaves that attract leafhopper vectors.

Leaf yellowing is a well-known phenotype that attracts phloem-feeding insects. However, it remains unclear how insect-vectored plant pathogens induce host leaf yellowing to facilitate their own transmission by insect vectors. Here, we report that an effector protein secreted by rice orange leaf phytoplasma (ROLP) inhibits chlorophyll biosynthesis and induces leaf yellowing to attract leafhopper vectors, thereby presumably promoting pathogen transmission. This effector, designated secreted ROLP protein 1 (SRP1), first secreted into rice phloem by ROLP, was subsequently translocated to chloroplasts by interacting with the chloroplastic glutamine synthetase (GS2). The direct interaction between SRP1 and GS2 disrupts the decamer formation of the GS2 holoenzyme, attenuating its enzymatic activity, thereby suppressing the synthesis of chlorophyll precursors glutamate and glutamine. Transgenic expression of SRP1 in rice plants decreased GS2 activity and chlorophyll precursor accumulation, finally inducing leaf yellowing. This process is correlated with the previous evidence that the knockout of GS2 expression in rice plants causes a similar yellow chlorosis phenotype. Consistently, these yellowing leaves attracted higher numbers of leafhopper vectors, caused the vectors to probe more frequently, and presumably facilitate more efficient phytoplasma transmission. Together, these results uncover the mechanism used by phytoplasmas to manipulate the leaf color of infected plants for the purpose of enhancing attractiveness to insect vectors.

CatLearning: highly accurate gene expression prediction from histone mark.

Histone modifications, known as histone marks, are pivotal in regulating gene expression within cells. The vast array of potential combinations of histone marks presents a considerable challenge in decoding the regulatory mechanisms solely through biological experimental approaches. To overcome this challenge, we have developed a method called CatLearning. It utilizes a modified convolutional neural network architecture with a specialized adaptation Residual Network to quantitatively interpret histone marks and predict gene expression. This architecture integrates long-range histone information up to 500Kb and learns chromatin interaction features without 3D information. By using only one histone mark, CatLearning achieves a high level of accuracy. Furthermore, CatLearning predicts gene expression by simulating changes in histone modifications at enhancers and throughout the genome. These findings help comprehend the architecture of histone marks and develop diagnostic and therapeutic targets for diseases with epigenetic changes.

PIPET: predicting relevant subpopulations in single-cell data using phenotypic information from bulk data.

Single-cell RNA sequencing has revealed cellular heterogeneity in complex tissues, notably benefiting research on diseases such as cancer. However, the integration of single-cell data from small samples with extensive clinical features in bulk data remains underexplored. In this study, we introduce PIPET, an algorithmic method for predicting relevant subpopulations in single-cell data based on multivariate phenotypic information from bulk data. PIPET generates feature vectors for each phenotype from differentially expressed genes in bulk data and then identifies relevant cellular subpopulations by assessing the similarity between single-cell data and these vectors. Subsequently, phenotype-related cell states can be analyzed based on these subpopulations. In simulated datasets, PIPET showed robust performance in predicting multiclassification cellular subpopulations. Application of PIPET to lung adenocarcinoma single-cell RNA sequencing data revealed cellular subpopulations with poor survival and associations with TP53 mutations. Similarly, in breast cancer single-cell data, PIPET identified cellular subpopulations associated with the PAM50 clinical subtypes and triple-negative breast cancer subtypes. Overall, PIPET effectively identified relevant cellular subpopulations in single-cell data, guided by phenotypic information from bulk data. This approach comprehensively delineates the molecular characteristics of each cellular subpopulation, offering insights into disease-related subpopulations and guiding personalized treatment strategies.

Multiplexed Antibody Glycosylation Profiling Using Dual Enzyme Digestion and Liquid Chromatography-Triple Quadrupole Mass Spectrometry Method.

Antibody glycosylation plays a crucial role in the humoral immune response by regulating effector functions and influencing the binding affinity to immune cell receptors. Previous studies have focused mainly on the immunoglobulin G (IgG) isotype owing to the analytical challenges associated with other isotypes. Thus, the development of a sensitive and accurate analytical platform is necessary to characterize antibody glycosylation across multiple isotypes. In this study, we have developed an analytical workflow using antibody-light-chain affinity beads to purify IgG, IgA, and IgM from 16 µL of human plasma. Dual enzymes, trypsin and Glu-C, were used during on-bead digestion to obtain enzymatic glycopeptides and protein-specific surrogate peptides. Ultra-high-performance liquid chromatography coupled with triple quadrupole mass spectrometry was used in order to determine the sensitivity and specificity. Our platform targets 95 glycopeptides across the IgG, IgA, and IgM isotypes, as well as eight surrogate peptides representing total IgG, four IgG classes, two IgA classes, and IgM. Four stable isotope-labeled internal standards were added after antibody purification to calibrate the preparation and instrumental bias during analysis. Calibration curves constructed using serially diluted plasma samples showed good curve fitting (R2 > 0.959). The intrabatch and interbatch precision for all the targets had relative standard deviation of less than 29.6%. This method was applied to 19 human plasma samples, and the glycosylation percentages were calculated, which were comparable to those reported in the literature. The developed method is sensitive and accurate for Ig glycosylation profiling. It can be used in clinical investigations, particularly for detailed humoral immune profiling.

ERK and c-Myc signaling in host-derived tumor endothelial cells is essential for solid tumor growth.

The limited efficacy of the current antitumor microenvironment strategies is due in part to the poor understanding of the roles and relative contributions of the various tumor stromal cells to tumor development. Here, we describe a versatile in vivo anthrax toxin protein delivery system allowing for the unambiguous genetic evaluation of individual tumor stromal elements in cancer. Our reengineered tumor-selective anthrax toxin exhibits potent antiproliferative activity by disrupting ERK signaling in sensitive cells. Since this activity requires the surface expression of the capillary morphogenesis protein-2 (CMG2) toxin receptor, genetic manipulation of CMG2 expression using our cell-type-specific CMG2 transgenic mice allows us to specifically define the role of individual tumor stromal cell types in tumor development. Here, we established mice with CMG2 only expressed in tumor endothelial cells (ECs) and determined the specific contribution of tumor stromal ECs to the toxin's antitumor activity. Our results demonstrate that disruption of ERK signaling only within tumor ECs is sufficient to halt tumor growth. We discovered that c-Myc is a downstream effector of ERK signaling and that the MEK-ERK-c-Myc central metabolic axis in tumor ECs is essential for tumor progression. As such, disruption of ERK-c-Myc signaling in host-derived tumor ECs by our tumor-selective anthrax toxins explains their high efficacy in solid tumor therapy.

Prostaglandin F2α drives female pheromone signaling in cichlids, revealing a basis for evolutionary divergence in olfactory signaling.

Pheromones play essential roles in reproduction in many species. Prostaglandin F2α (PGF2α) acts as a female reproductive hormone and as a sex pheromone in some species. An olfactory receptor (OR) for PGF2α was recently discovered in zebrafish, but this signaling pathway is evolutionarily labile. To understand the evolution of signals that attract males to fertile females, we used the African cichlid Astatotilapia burtoni and found that adult males strongly prefer fertile female odors. Injection of a prostaglandin synthesis inhibitor abolishes this attractivity of fertile females, indicating these hormones are necessary for pheromonal signaling. Unlike zebrafish, A. burtoni males are insensitive to PGF2α, but they do exhibit strong preference for females injected with PGF2α. This attractiveness is independent of the PGF2α hormonal receptor Ptgfr, indicating that this pheromone signaling derives from PGF2α metabolization into a yet-undiscovered pheromone. We further discovered that fish that are insensitive to PGF2α lack an ortholog for the OR Or114 that zebrafish use to detect PGF2α. These results indicate that PGF2α itself does not directly induce male preference in cichlids. Rather, it plays a vital role that primes females to become attractive via an alternative male OR.

Multilayered gene control drives timely exit from the stem cell state in uncommitted progenitors during Drosophila asymmetric neural stem cell division.

Self-renewal genes maintain stem cells in an undifferentiated state by preventing the commitment to differentiate. Robust inactivation of self-renewal gene activity following asymmetric stem cell division allows uncommitted stem cell progeny to exit from an undifferentiated state and initiate the commitment to differentiate. Nonetheless, how self-renewal gene activity at mRNA and protein levels becomes synchronously terminated in uncommitted stem cell progeny is unclear. We demonstrate that a multilayered gene regulation system terminates self-renewal gene activity at all levels in uncommitted stem cell progeny in the fly neural stem cell lineage. We found that the RNA-binding protein Brain tumor (Brat) targets the transcripts of a self-renewal gene, deadpan (dpn), for decay by recruiting the deadenylation machinery to the 3' untranslated region (UTR). Furthermore, we identified a nuclear protein, Insensible, that complements Cullin-mediated proteolysis to robustly inactivate Dpn activity by limiting the level of active Dpn through protein sequestration. The synergy between post-transcriptional and transcriptional control of self-renewal genes drives timely exit from the stem cell state in uncommitted progenitors. Our proposed multilayered gene regulation system could be broadly applicable to the control of exit from stemness in all stem cell lineages.

A novel RAV transcription factor from pear interacts with viral RNA-silencing suppressors to inhibit viral infection.

In plants, RNA silencing constitutes a strong defense against viral infection, which viruses counteract with RNA-silencing suppressors (RSSs). Understanding the interactions between viral RSSs and host factors is crucial for elucidating the molecular arms race between viruses and host plants. We report that the helicase motif (Hel) of the replicase encoded by apple stem grooving virus (ASGV)-the main virus affecting pear trees in China-is an RSS that can inhibit both local and systemic RNA silencing, possibly by binding double-stranded (ds) siRNA. The transcription factor related to ABSCISIC ACID INSENSITIVE3/VIVIPAROUS1 from pear (PbRAV1) enters the cytoplasm and binds Hel through its C terminus, thereby attenuating its RSS activity by reducing its binding affinity to 21- and 24-nt ds siRNA, and suppressing ASGV infection. PbRAV1 can also target p24, an RSS encoded by grapevine leafroll-associated virus 2 (GLRaV-2), with similar negative effects on p24's suppressive function and inhibition of GLRaV-2 infection. Moreover, like the positive role of the PbRAV1 homolog from grapevine (VvRAV1) in p24's previously reported RSS activity, ASGV Hel can also hijack VvRAV1 and employ the protein to sequester 21-nt ds siRNA, thereby enhancing its own RSS activity and promoting ASGV infection. Furthermore, PbRAV1 neither interacts with CP, an RSS encoded by grapevine inner necrosis virus, nor has any obvious effect on CP's RSS activity. Our results identify an RSS encoded by ASGV and demonstrate that PbRAV1, representing a novel type of RAV transcription factor, plays a defensive role against viral infection by targeting viral RSSs.

Brain Gene Regulatory Networks Coordinate Nest Construction in Birds.

Nest building is a vital behavior exhibited during breeding in birds, and is possibly induced by environmental and social cues. Although such behavioral plasticity has been hypothesized to be controlled by adult neuronal plasticity, empirical evidence, especially at the neurogenomic level, remains limited. Here, we aim to uncover the gene regulatory networks that govern avian nest construction and examine whether they are associated with circuit rewiring. We designed an experiment to dissect this complex behavior into components in response to pair bonding and nest material acquisition by manipulating the presence of mates and nest materials in 30 pairs of zebra finches. Whole-transcriptome analysis of 300 samples from five brain regions linked to avian nesting behaviors revealed nesting-associated gene expression enriched with neural rewiring functions, including neurogenesis and neuron projection. The enriched expression was observed in the motor/sensorimotor and social behavior networks of female finches, and in the dopaminergic reward system of males. Female birds exhibited predominant neurotranscriptomic changes to initiate the nesting stage, while males showed major changes after entering this stage, underscoring sex-specific roles in nesting behavior. Notably, major neurotranscriptomic changes occurred during pair bonding, with minor changes during nest material acquisition, emphasizing social interactions in nest construction. We also revealed gene expression associated with reproductive behaviors and tactile sensing for nesting behavior. This study presents novel neurogenomic evidence supporting the hypothesis of adult neural plasticity underlying avian nest-construction behavior. By uncovering the genetic toolkits involved, we offer novel insights into the evolution of animals' innate ability to construct nests.

Creep-free polyelectrolyte elastomer for drift-free iontronic sensing.

Artificial pressure sensors often use soft materials to achieve skin-like softness, but the viscoelastic creep of soft materials and the ion leakage, specifically for ionic conductors, cause signal drift and inaccurate measurement. Here we report drift-free iontronic sensing by designing and copolymerizing a leakage-free and creep-free polyelectrolyte elastomer containing two types of segments: charged segments having fixed cations to prevent ion leakage and neutral slippery segments with a high crosslink density for low creep. We show that an iontronic sensor using the polyelectrolyte elastomer barely drifts under an ultrahigh static pressure of 500 kPa (close to its Young's modulus), exhibits a drift rate two to three orders of magnitude lower than that of the sensors adopting conventional ionic conductors and enables steady and accurate control for robotic manipulation. Such drift-free iontronic sensing represents a step towards highly accurate sensing in robotics and beyond.

N6-methyladenosine RNA modification regulates photoperiod sensitivity in cotton.

The methylation of N6-methyladenosine (m6A) involves writers, erasers, and readers, acting synergistically in posttranscriptional regulation. These processes influence various biological processes, including plant floral transition. However, the specific role of m6A modifications in photoperiod sensitivity in cotton (Gossypium hirsutum) remains obscure. To elucidate this, in this study, we conducted transcriptome-wide m6A sequencing during critical flowering transition stages in the photoperiod-sensitive wild G. hirsutum var. yucatanense (yucatanense) and the photoperiod-insensitive cultivated cotton G. hirsutum acc. TM-1 (TM-1). Our results revealed significant variations in m6A methylation of 2 cotton varieties, with yucatanense exhibiting elevated m6A modification levels compared with TM-1 under long-day conditions. Notably, distinct m6A peaks between TM-1 and yucatanense correlated significantly with photoperiod sensitivity. Moreover, our study highlighted the role of the demethylase G. hirsutum ALKB homolog 5 (GhALKBH5) in modulating m6A modification levels. Silencing GhALKBH5 led to a decreased mRNA level of key photoperiodic flowering genes (GhADO3, GhAGL24, and GhFT1), resulting in delayed bud emergence and flowering. Reverse transcription quantitative PCR analyses confirmed that silencing GhADO3 and GhAGL24 significantly downregulated the expression of the floral integrator GhFT1. Collectively, our findings unveiled a transcriptional regulatory mechanism in which GhALKBH5-mediated m6A demethylation of crucial photoperiodic flowering transcripts modulated photoperiod sensitivity in cotton.

Exosomes derived from umbilical cord-derived mesenchymal stem cells exposed to diabetic microenvironment enhance M2 macrophage polarization and protect against diabetic nephropathy.

The role of mesenchymal-stem-cell-derived exosomes (MSCs-Exo) in the regulation of macrophage polarization has been recognized in several diseases. There is emerging evidence that MSCs-Exo partially prevent the progression of diabetic nephropathy (DN). This study aimed to investigate whether exosomes secreted by MSCs pre-treated with a diabetic environment (Exo-pre) have a more pronounced protective effect against DN by regulating the balance of macrophages. Exo-pre and Exo-Con were isolated from the culture medium of UC-MSCs pre-treated with a diabetic mimic environment and natural UC-MSCs, respectively. Exo-pre and Exo-Con were injected into the tail veins of db/db mice three times a week for 6 weeks. Serum creatinine and serum urea nitrogen levels, the urinary protein/creatinine ratio, and histological staining were used to determine renal function and morphology. Macrophage phenotypes were analyzed by immunofluorescence, western blotting, and quantitative reverse transcription polymerase chain reaction. In vitro, lipopolysaccharide-induced M1 macrophages were incubated separately with Exo-Con and Exo-pre. We performed microRNA (miRNA) sequencing to identify candidate miRNAs and predict their target genes. An miRNA inhibitor was used to confirm the role of miRNAs in macrophage modulation. Exo-pre were more potent than Exo-Con at alleviating DN. Exo-pre administration significantly reduced the number of M1 macrophages and increased the number of M2 macrophages in the kidney compared to Exo-Con administration. Parallel outcomes were observed in the co-culture experiments. Moreover, miR-486-5p was distinctly expressed in Exo-Con and Exo-pre groups, and it played an important role in macrophage polarization by targeting PIK3R1 through the PI3K/Akt pathway. Reducing miR-486-5p levels in Exo-pre abolished macrophage polarization modulation. Exo-pre administration exhibited a superior effect on DN by remodeling the macrophage balance by shuttling miR-486-5p, which targets PIK3R1.

Rapid evolutionary repair by secondary perturbation of a primary disrupted transcriptional network.

The discrete steps of transcriptional rewiring have been proposed to occur neutrally to ensure steady gene expression under stabilizing selection. A conflict-free switch of a regulon between regulators may require an immediate compensatory evolution to minimize deleterious effects. Here, we perform an evolutionary repair experiment on the Lachancea kluyveri yeast sef1Δ mutant using a suppressor development strategy. Complete loss of SEF1 forces cells to initiate a compensatory process for the pleiotropic defects arising from misexpression of TCA cycle genes. Using different selective conditions, we identify two adaptive loss-of-function mutations of IRA1 and AZF1. Subsequent analyses show that Azf1 is a weak transcriptional activator regulated by the Ras1-PKA pathway. Azf1 loss-of-function triggers extensive gene expression changes responsible for compensatory, beneficial, and trade-off phenotypes. The trade-offs can be alleviated by higher cell density. Our results not only indicate that secondary transcriptional perturbation provides rapid and adaptive mechanisms potentially stabilizing the initial stage of transcriptional rewiring but also suggest how genetic polymorphisms of pleiotropic mutations could be maintained in the population.

Prenylated PALM2 Promotes the Migration of Esophageal Squamous Cell Carcinoma Cells Through Activating Ezrin.

Proteins containing a CAAX motif at the C-terminus undergo prenylation for localization and activity and include a series of key regulatory proteins, such as RAS superfamily members, heterotrimeric G proteins, nuclear lamina protein, and several protein kinases and phosphatases. However, studies of prenylated proteins in esophageal cancer are limited. Here, through research on large-scale proteomic data of esophageal cancer in our laboratory, we found that paralemmin-2 (PALM2), a potential prenylated protein, was upregulated and associated with poor prognosis in patients. Low-throughput verification showed that the expression of PALM2 in esophageal cancer tissues was higher than that in their paired normal esophageal epithelial tissues, and it was generally expressed in the membrane and cytoplasm of esophageal cancer cells. PALM2 interacted with the two subunits of farnesyl transferase (FTase), FNTA and FNTB. Either the addition of an FTase inhibitor or mutation in the CAAX motif of PALM2 (PALM2C408S) impaired its membranous localization and reduced the membrane location of PALM2, indicating PALM2 was prenylated by FTase. Overexpression of PALM2 enhanced the migration of esophageal squamous cell carcinoma cells, whereas PALM2C408S lost this ability. Mechanistically, PALM2 interacted with the N-terminal FERM domain of ezrin of the ezrin/radixin/moesin (ERM) family. Mutagenesis indicated that lysine residues K253/K254/K262/K263 in ezrin's FERM domain and C408 in PALM2's CAAX motif were important for PALM2/ezrin interaction and ezrin activation. Knockout of ezrin prevented enhanced cancer cell migration by PALM2 overexpression. PALM2, depending on its prenylation, increased both ezrin membrane localization and phosphorylation of ezrin at Y146. In summary, prenylated PALM2 enhances the migration of cancer cells by activating ezrin.

The arginine methyltransferase Prmt1 coordinates the germline arginine methylome essential for spermatogonial homeostasis and male fertility.

Arginine methylation, catalyzed by the protein arginine methyltransferases (PRMTs), is a common post-translational protein modification (PTM) that is engaged in a plethora of biological events. However, little is known about how the methylarginine-directed signaling functions in germline development. In this study, we discover that Prmt1 is predominantly distributed in the nuclei of spermatogonia but weakly in the spermatocytes throughout mouse spermatogenesis. By exploiting a combination of three Cre-mediated Prmt1 knockout mouse lines, we unravel that Prmt1 is essential for spermatogonial establishment and maintenance, and that Prmt1-catalyzed asymmetric methylarginine coordinates inherent transcriptional homeostasis within spermatogonial cells. In conjunction with high-throughput CUT&Tag profiling and modified mini-bulk Smart-seq2 analyses, we unveil that the Prmt1-deposited H4R3me2a mark is permissively enriched at promoter and exon/intron regions, and sculpts a distinctive transcriptomic landscape as well as the alternative splicing pattern, in the mouse spermatogonia. Collectively, our study provides the genetic and mechanistic evidence that connects the Prmt1-deposited methylarginine signaling to the establishment and maintenance of a high-fidelity transcriptomic identity in orchestrating spermatogonial development in the mammalian germline.

A mutation-sensitive, multiplexed and amplification-free detection of nucleic acids by stretching single-molecule tandem hairpin probes.

The detection of nucleic acid sequences in parallel with the discrimination of single nucleotide variations (SNVs) is critical for research and clinical applications. A few limitations make the detection technically challenging, such as too small variation in probe-hybridization energy caused by SNVs, the non-specific amplification of false nucleic acid fragments and the few options of dyes limited by spectral overlaps. To circumvent these limitations, we developed a single-molecule nucleic acid detection assay without amplification or fluorescence termed THREF (hybridization-induced tandem DNA hairpin refolding failure) based on multiplexed magnetic tweezers. THREF can detect DNA and RNA sequences at femtomolar concentrations within 30 min, monitor multiple probes in parallel, quantify the expression level of miR-122 in patient tissues, discriminate SNVs including the hard-to-detect G-U or T-G wobble mutations and reuse the probes to save the cost. In our demonstrative detections using mock clinic samples, we profiled the let-7 family microRNAs in serum and genotyped SARS-CoV-2 strains in saliva. Overall, the THREF assay can discriminate SNVs with the advantages of high sensitivity, ultra-specificity, multiplexing, reusability, sample hands-free and robustness.

Un-methylation of NUDT21 represses docosahexaenoic acid biosynthesis contributing to enzalutamide resistance in prostate cancer.

AIMS: The recent approval of enzalutamide for metastatic castration-sensitive prostate cancer underscores its growing clinical significance, raising concerns about emerging resistance and limited treatment options. While the reactivation of the androgen receptor (AR) and other genes plays a role in enzalutamide resistance, identifications of novel underlying mechanism with therapeutic potential in enzalutamide-resistant (EnzaR) cells remain largely elusive. METHODS: Drug-resistant prostate cancer cell lines, animal models, and organoids were utilized to examine NUDT21 function by transcriptomic and metabolomic analyses through loss-of-function and gain-of-function assays. Notably, a mono-methylation monoclonal antibody and conditional-knockin transgenic mouse model of NUDT21 were generated for evaluating its function. RESULTS: NUDT21 overexpression acts as a crucial alternative polyadenylation (APA) mediator, supported by its oncogenic role in prostate cancer. PRMT7-mediated mono-methylation of NUDT21 induces a shift in 3'UTR usage, reducing oncogenicity. In contrast, its un-methylation promotes cancer growth and cuproptosis insensitivity in EnzaR cells by exporting toxic copper and suppressing docosahexaenoic acid (DHA) biosynthesis. Crucially, NUDT21 inhibition or DHA supplementation with copper ionophore holds therapeutic promise for EnzaR cells. CONCLUSIONS: The un-methylation of NUDT21-mediated 3'UTR shortening unveils a novel mechanism for enzalutamide resistance, and our findings offer innovative strategies for advancing the treatment of prostate cancer patients experiencing enzalutamide resistance.