Biology subjects

Cui, Y.

Publications and source records attributed to Cui, Y..

At least 127 records · Page 7Linked to original sources

bioRxiv2023

NUCLEOPORIN1 mediates proteasome-based degradation of ABI5 to regulate Arabidopsis seed germination

NUCLEOPORIN1 (NUP1), a member of the Nuclear Pore Complex (NPC), is located on the inner side of the nuclear membrane. It is highly expressed in seeds; however, its role in seeds including germination has not been explored yet. Here, we identified an abscisic acid (ABA) hypersensitive phenotype of nup1 during germination. ABA treatment drastically changes the expression pattern of thousands of genes in nup1, including the major transcription factors (TFs) involved in germination, ABI3, ABI4, and ABI5. Double mutant analysis of NUP1 and these ABA-related genes showed that mutations in ABI5 can rescue the phenotype of nup1, suggesting that NUP1 acts upstream of ABI5 to regulate seed germination. ABI5, a key negative regulator of germination, is abundant in dry seeds and rapidly degrades during germination. However, its spatiotemporal regulation and interaction with other molecular players during degradation remained to be fully elucidated. We found that NUP1 is physically associated with ABI5 and the 26S proteasome. Mutation in NUP1 delayed ABI5 degradation through its post-translational retention in nucleolus under abiotic stress. Taken together, our findings suggest that NUP1 anchors the proteasome to NPC and modulates seed germination through proteasome-mediated degradation of ABI5 in the vicinity of NPC in the nucleoplasm.

plant biology↗

bioRxiv2023

Anopheles gambiae mosGILT regulates innate immune genes and zpg expression

Gene-edited mosquitoes lacking a gamma-interferon-inducible lysosomal thiol reductase-like protein, namely (mosGILTnull) have lower Plasmodium infection, which is linked to impaired ovarian development and immune activation. The transcriptome of mosGILTnull A. gambiae was therefore compared to wild type (WT) by RNA-sequencing to delineate mosGILT-dependent pathways. Compared to WT mosquitoes, mosGILTnull A. gambiae demonstrated altered expression of genes related to oogenesis, 20-hydroxyecdysone synthesis, as well as immune-related genes. Serendipitously, the zero population growth gene, zpg, an essential regulator of germ cell development was found to be one of the most downregulated genes in mosGILTnull mosquitoes. These results provide the crucial missing link between two previous studies on the role of zpg and mosGILT in ovarian development. This study further demonstrates that mosGILT has the potential to serve as a target for the biological control of mosquito vectors and to influence the Plasmodium life cycle within the vector.

genomics↗

bioRxiv2023

Metabolomic changes associated with acquired resistance to Ixodes scapularis

Guinea pigs repeatedly exposed to Ixodes scapularis develop acquired resistance to the ticks (ATR). The molecular mechanisms of ATR have not been fully elucidated, and partially involve immune responses to proteins in tick saliva. In this study, we examined the metabolome of sera of guinea pigs during the development of ATR. Induction of components of the tyrosine metabolic pathway, including hydroxyphenyllactic acid (HPLA), were associated with ATR. We therefore administered HPLA to mice, an animal that does not develop ATR, and exposed the animals to I. scapularis. We also administered nitisinone, a known inhibitor of tyrosine degradation, to another group of mice. The mortality of I. scapularis that fed on mice given HPLA or nitisinone was 26% and 72% respectively, compared with 2% mortality among ticks that fed on control animals. These data indicate that metabolic changes that occur after tick bites contribute to ATR.

biochemistry↗

bioRxiv2023

Competitive fitness and homologous recombination of SARS-CoV-2 variants of concern

SARS-CoV-2 variants continue to emerge and cocirculate in humans and wild animals. The factors driving the emergence and replacement of novel variants and recombinants remain incompletely understood. Herein, we comprehensively characterized the competitive fitness of SARS-CoV-2 wild type (WT) and three variants of concern (VOCs), Alpha, Beta and Delta, by coinfection and serial passaging assays in different susceptible cells. Deep sequencing analyses revealed cell-specific competitive fitness: the Beta variant showed enhanced replication fitness during serial passage in Caco-2 cells, whereas the WT and Alpha variant showed elevated fitness in Vero E6 cells. Interestingly, a high level of neutralizing antibody sped up competition and completely reshaped the fitness advantages of different variants. More importantly, single clone purification identified a significant proportion of homologous recombinants that emerged during the passage history, and immune pressure reduced the frequency of recombination. Interestingly, a recombination hot region located between nucleotide sites 22995 and 28866 of the viral genomes could be identified in most of the detected recombinants. Our study not only profiled the variable competitive fitness of SARS-CoV-2 under different conditions, but also provided direct experimental evidence of homologous recombination between SARS-CoV-2 viruses, as well as a model for investigating SARS-CoV-2 recombination. ImportanceSARS-CoV-2 variants or subvariants keep emerging and the epidemic strains keeps changing in humans and animals. The continued replacement of the epidemic strains was attributed to higher competitive fitness evolved by the newly appeared ones than the older ones, but which factors affect the final outcomes are still not entirely clear. In this study, we performed in vitro coinfection and serial passage with three VOCs and WT under different conditions. Our results showed that the competition outcomes of these viral strains varied in different cell lines or under different immune pressure, confirming the probable effects of these two factors for the competitive fitness of different SARS-CoV-2 viral strains. Meanwhile, strikingly, we found that coinfection and serial passage with different SARS-CoV-2 viral strains can mimic the recombination process of SARS-CoV-2 occurred in coinfection individual, indicating it is a novel model to investigate the SARS-CoV-2 recombination mechanism.

microbiology↗

bioRxiv2023

Variations in Homoeologous Dosage and Epigenomics Mark the Early Evolution of Synthetic Brassica Tetraploids

Polyploidization is important in plant evolution and is becoming increasingly important in crop breeding and material creation. Studies have provided evidence for structural variations and epigenomic repatterning in synthetic polyploidizations, but the relationships between structural and epigenomic variations, as well as their effects on gene expression and phenotypic variations are unknown. Here, we investigated the genome-wide large deletion/duplication regions (DelDups) and genomic methylation dynamics, in the leaf organ as a representative, of progenies from eight generations that derived from the synthetic tetraploidization between Brassica rapa and Brassica oleracea. We found that half or complete deletion/duplication of fragments ranging in size from 400 kb to 65.85 Mb, with a mean size of 5.70 Mb, occurred frequently from the first generation of selfing and thereafter. The genes located in these DelDups expressed at levels expected for a positive dosage effect, as indicated by the positive association between expression and the copy number of these genes. Plants containing these DelDups also showed distinct phenotypic variations. The whole genome methylation level experienced significant fluctuations in different generations and eventually decreased in the latter generations. Moreover, the DelDups did not show methylation changes from other individuals of the same generation, and the local regions with methylation alterations did not affect gene expression. Our findings provide new insights into the early evolution of polyploid genomes and guide the use of synthetic polyploidizations in breeding.

genomics↗

bioRxiv2023

Establishment of a novel non-integrated human pluripotent stem cell-based gastruloid model

Embryo loss and pregnancy disorders are prevalent worldwide, with both conditions critically associated with dysfunctioning gastrulation processes. Gastrulation and post-gastrulation organogenesis are crucial stages of embryonic development that establish the blueprint for body part formation. These processes involve the sequential generation of three germ layer cells and primordial germ cells, as well as the assembly of the precursor tissues for body parts. However, due to ethical limitations associated with studying human embryogenesis, a more detailed understanding of gastrulation and post-gastrulation organogenesis remains elusive. To ensure that the knowledge obtained from gastruloids is biologically meaningful and clinically relevant, it is critical to create high-fidelity human embryo models that closely mimic embryogenesis in vivo. Here, we developed a two-stage derivation gastruloids in vitro based on human pluripotent stem cells. Morphological tracking mimicks the developmental processes of models from Carnegie Stage 4 (CS4) to early CS7. Our gastruloids exhibit key structures characteristic of human embryos, including amniotic cavity, embryonic disc, primitive streak, primary yolk sac, secondary yolk sac, and blood islets. Comparison of our cell lineage development maps showed that gastruloids closely resembled human natural CS7 gastrula. Our gastruloids exhibited transcriptional characteristics that mimicked the molecular pathways observed in natural embryos development. Importantly, we found that in our model, extraembryonic mesoderm originates from the yolk sac and primordial germ cells originate from the posterior epiblast of the embryonic disc. Moreover, we found that thalidomide affects the differentiation of three germ layer cells, resulting in the arrest of human gastruloid development. In conclusion, by establishing a human gastruloid, we were able to gain valuable insights into the mechanisms responsible for human gastrulation and shed light on the causes of early embryo loss and pregnancy disorders.

developmental biology↗

bioRxiv2023

Opioidergic activation of descending pain inhibitory system underlies placebo analgesia

Placebo analgesia is caused by inactive treatment, implicating endogenous brain function involvement. However, the underlying neurobiological mechanisms remain unclear. We found that -opioid signals in the medial prefrontal cortex (mPFC) activate the descending pain inhibitory system to initiate placebo analgesia in neuropathic pain rats. Chemogenetic manipulation demonstrated that specific activation of -opioid receptor-positive (MOR+) neurons in the mPFC or suppression of the mPFC-ventrolateral periaqueductal gray (vlPAG) circuit inhibited placebo analgesia in rats. MOR+ neurons in the mPFC are monosynaptically connected and directly inhibit L5 pyramidal neurons that project to the vlPAG via GABAA receptors. Thus, intrinsic opioid signaling in the mPFC disinhibits excitatory outflow to the vlPAG by suppressing MOR+ neurons, leading to descending pain inhibitory system activation that initiates placebo analgesia. One Sentence SummarySugar pills relieve pain by activating the intrinsic pain inhibitory system via opioidergic signals in the prefrontal cortex.

neuroscience↗

bioRxiv2023

SWI/SNF chromatin remodeling determines brassinosteroid-induced transcriptional activation

The brassinosteroid (BR) hormone is a central modulator of plant growth, development, and responses to stresses by activating or repressing the expression of thousands of genes through the transcription factor BRASSINAZOLE-RESISTANT 1 (BZR1) and its homologues. However, the molecular mechanism that determines the transcriptional activation versus repression activity of BZR1 remains largely unclear. Here, we show that BZR1-responsive transcriptional activation at thousands of loci requires the Switch defective/sucrose non-fermentable (SWI/SNF)-complexes-mediated chromatin accessibility regulation. BR-activated BZR1 controls the activation or repression of thousands of BZR1 target genes through reprograming genome-wide chromatin accessibility landscape in Arabidopsis thaliana. BZR1 physically interacts with the BRAHMA (BRM)-Associated SWI/SNF complexes (BAS), co-localizes with BRM on the genome, and enhances BRM occupancy at sites of increased accessibility by BR. Loss of BRM abrogates the capacity of BZR1 to increase but not decrease chromatin accessibility, blocks BR-induced hypocotyl elongation, and diminishes BZR1-mediated transcriptional activation rather than repression. Together, our work reveals that the BAS chromatin remodeling complex is a critical epigenetic regulatory partner in dictating BZR1-mediated transcriptional activation ability, thus providing a long sought mechanistic explanation for how BR signaling activates gene transcription in shaping diverse developmental programs. TeaserBZR1-responsive transcriptional activation activity at thousands of loci requires the SWI/SNF-complexes-mediated chromatin accessibility regulation.

plant biology↗

bioRxiv2023

Biochemical and chemical biological approaches to mammalian sleep: roles of calcineurin in site-specific dephosphorylation and sleep regulation

Understanding of sleep mechanisms traditionally rely on electrophysiology and genetics but here we have initiated biochemical and chemical biological studies. Sleep was increased in mouse mutants with an alanine replacing threonine at residue 469 (T469A) of the salt inducible kinase 3 (SIK3). We searched for T469 phosphatases by classic purification with HEK293 cells and by a new photo-crosslinking method with mouse brains. Both led to PPP3CA, a catalytic subunit of calcium/calmodulin activated phosphatase (calcineurin). It dephosphorylated T469 and serine (S) 551 but not T221 in SIK3 in vitro. PPP3CA knockdown increased phosphorylation of T469 and S551 but not T221 in mouse brains. Knockdown of its regulatory subunit PPP3R1 significantly reduced daily sleep by more than 5 hours, exceeding other known mouse mutants. Our results have uncovered in vitro and in vivo evidence for site-specific SIK3 dephosphorylation by calcineurin, demonstrated a physiological role for calcineurin in sleep, and suggested sleep control by calcium dependent dephosphorylation.

neuroscience↗

bioRxiv2023

Select EZH2 inhibitors enhance the viral mimicry effects of DNMT inhibition through a mechanism involving calcium-calcineurin-NFAT signaling

DNA methyltransferase (DNMT) inhibitors are FDA-approved for various hematological malignancies but have limited efficacy in solid tumors. DNA hypomethylation with these drugs is associated with elevated lysine 27 tri-methylation on histone H3 (H3K27me3). We hypothesized that this EZH2-dependent repressive mark limits the full potential of DNMT inhibition. Here, we show in cell line and tumoroid models of colorectal cancer, that low-dose DNMT inhibition sensitizes cells to selective EZH2 inhibitors that have limited single agent toxicity, and that EZH2 inhibition enhances DNMT inhibitor-driven molecular and therapeutic effects. Through integrative epigenomic analyses, we reveal that DNMT inhibition induces H3K27me3 accumulation at genomic regions poised with EZH2. Unexpectedly, combined treatment alters the epigenome landscape to promote transcriptional upregulation of the calcium-calcineurin-NFAT signaling pathway. Blocking this pathway limits the transcriptional activating effects of the drug combination, including expression of transposable elements and innate immune response genes within a viral defense pathway. Consistently, we demonstrate positive correlations between DNMT inhibitor- and innate immune response-associated transcription profiles and calcium signal activation in primary human colon cancer specimens. Collectively, our study demonstrates that compensatory EZH2 activity following DNA hypomethylation presents a barrier to the therapeutic action of DNMT inhibition in colon cancer, reveals a new application of EZH2 inhibitors beyond cancers associated with PRC2 hyperactivity, and links calcium-calcineurin-NFAT signaling to epigenetic therapy-induced viral mimicry. HighlightsO_LISelect EZH2 inhibitors enhance the transcriptional activating and antiproliferative effects of DNA hypomethylating agents in colon cancer cells. C_LIO_LIThe mechanism involves blockade of H3K27me3 accumulation in regions of the genome poised for PRC2 activity. C_LIO_LIDNMT inhibitor + EZH2 inhibitor treatment transcriptionally upregulates calcium-calcineurin- NFAT signaling, and this pathway is necessary for complete induction of viral mimicry and innate immune response pathways. C_LIO_LIThe therapeutic utility of EZH2 inhibitors may be extended beyond cancers with PRC2 hyperactivity in combination regimens with DNMT inhibitors. C_LI

cancer biology↗

bioRxiv2023

Tumor-specific neutrophils originating from meninges promote glioblastoma

Glioma is one of the most aggressive human cancers with limited therapeutic options. Though research has extensively examined immune components in those malignant tumors, the pathophysiological mechanism establishing their immunosuppressive microenvironment remains incompletely characterized. In this study, we report for the first time the unique presence of tumor-specific neutrophils (TSNs) in human glioblastoma (GBM) tumors. This newly defined neutrophil subtype exhibits the high expression of several immunosuppressive genes (e.g., CD274 and IDO1) and is strongly correlated with glioma grades and poor prognosis of patients. TSNs with comparable gene signatures are similarly present in the tumors but not bone marrow or spleen of mouse glioma models. Blockage of TSN recruitment by either Cxcl1-knockout in glioma cells or Cxcr2-deletion in host mice significantly enhances antitumor immunity and inhibits tumor progression. Surprisingly, we further identify the meninges as the key extratumoral source of generating TSNs in both human GBM patients and mouse glioma models. These results have elucidated a novel mechanism of neutrophils designating the tumor immune microenvironment and the essential link of meningeal immunity to glioma.

cancer biology↗

bioRxiv2023

Vaccination with mycobacterial lipid loaded nanoparticle leads to lipid antigen persistence and memory differentiation of antigen-specific T cells

Mycobacterium tuberculosis (Mtb) infection elicits both protein and lipid antigen-specific T cell responses. However, the incorporation of lipid antigens into subunit vaccine strategies and formulations has been underexplored, and the characteristics of vaccine-induced Mtb lipid-specific memory T cells have remained elusive. Mycolic acid (MA), a major lipid component of the Mtb cell wall, is presented by human CD1b molecules to unconventional T cell subsets. These MA-specific CD1b-restricted T cells have been detected in the blood and disease sites of Mtb-infected individuals, suggesting that MA is a promising lipid antigen for incorporation into multicomponent subunit vaccines. In this study, we utilized the enhanced stability of bicontinuous nanospheres (BCN) to efficiently encapsulate MA for in vivo delivery to MA-specific T cells, both alone and in combination with an immunodominant Mtb protein antigen (Ag85B). Pulmonary administration of MA-loaded BCN (MA-BCN) elicited MA-specific T cell responses in humanized CD1 transgenic mice. Simultaneous delivery of MA and Ag85B within BCN activated both MA- and Ag85B-specific T cells. Notably, pulmonary vaccination with MA-Ag85B-BCN resulted in the persistence of MA, but not Ag85B, within alveolar macrophages in the lung. Vaccination of MA-BCN through intravenous or subcutaneous route, or with attenuated Mtb likewise reproduced MA persistence. Moreover, MA-specific T cells in MA-BCN-vaccinated mice differentiated into a T follicular helper-like phenotype. Overall, the BCN platform allows for the dual encapsulation and in vivo activation of lipid and protein antigen-specific T cells and leads to persistent lipid depots that could offer long-lasting immune responses.

immunology↗

bioRxiv2023

Working memory-based and -free reward prediction in a dual dopamine system in the basal ganglia

Animals optimize their actions by predicting and verifying their outcomes (e.g., rewards). Reward prediction often requires working memory (WM)-based information. To elucidate the neural basis of WM-based reward prediction, we compared the activity of dopamine (DA) neurons in the ventral tegmental area (VTA) in an alternate reward condition (WM-based) with that in a random (WM-free) reward condition in rats and mice. Positron emission tomography revealed greater VTA activation in the WM-based than the WM-free condition. Lateral and medial VTA neurons displayed differential electrophysiological spike activities reflecting WM-based and WM-free reward prediction error, respectively. Furthermore, phasic DA release in the dorsal and ventral striatum changed as WM-based and WM-free classical conditioning progressed. Consistent with our WM-based model, reward acquisition caused a DA dip only in the dorsal striatum. Thus a dual DA system processes WM-based and WM-free reward prediction in parallel.

neuroscience↗

bioRxiv2023

Neutralization of SARS-CoV-2 BQ.1.1 and XBB.1.5 by Breakthrough Infection Sera from Previous and Current Waves in China

SARS-CoV-2 is continuing to evolve and diversify, with an array of various Omicron sub-lineages, including BA.5, BA.2.75, BN.1, BF.7, BQ.1, BQ.1.1, XBB and XBB.1.5, now circulating globally at recent time. In this study, we evaluated the neutralization sensitivity of a comprehensive panel of Omicron subvariants to sera from different clinical cohorts, including individuals who received homologous or heterologous booster vaccinations, vaccinated people who had Delta or BA.2 breakthrough infection in previous waves, and patients who had BA.5 or BF.7 breakthrough infection in the current wave in China. All the Omicron subvariants exhibited substantial neutralization evasion, with BQ.1, BQ.1.1, XBB.1, and XBB.1.5 being the strongest escaped subvariants. Sera from Omicron breakthrough infection, especially the recent BA.5 or BF.7 breakthrough infection, exhibited higher neutralizing activity against all Omicron sub-lineages, indicating the chance of BA.5 and BF.7 being entirely replaced by BQ or XBB subvariants in China in a short-term might be low. We also demonstrated that the BQ and XBB subvariants were the most resistant viruses to monoclonal antibodies. Continuing to monitor the immune escape of SARS-CoV-2 emerging variants and developing novel broad-spectrum vaccines and antibodies are still crucial.

immunology↗

bioRxiv2023

Three-dimensional morphological analysis revealed the cell patterning bases for the sexual dimorphism development in the liverwort Marchantia polymorpha

In land plants, sexual dimorphism can develop in both diploid sporophytes and haploid gametophytes. While developmental processes of sexual dimorphism have been extensively studied in the sporophytic reproductive organs of model flowering plants such as stamens and carpels of Arabidopsis thaliana, those occurring in gametophyte generation are less well characterized due to the lack of amenable model systems. We here performed three-dimensional morphological analyses of gametophytic sexual branch differentiation in the liverwort Marchantia polymorpha, using high-depth confocal imaging and a computational cell segmentation technique. Our analysis revealed that specification of germline precursors initiates in a very early stage of sexual branch development where incipient branch primordia are barely recognizable in the apical notch region. Moreover, spatial distribution patterns of germline precursors differ between males and females from the initial stage of primordium development in a manner dependent on the master sexual differentiation regulator MpFGMYB. In later stages, distribution patterns of germline precursors predict the sex-specific gametangia arrangement and receptacle morphologies seen in mature sexual branches. Taken together, our data suggests a tightly coupled progression of germline segregation and sexual dimorphism development in M. polymorpha.

plant biology↗

bioRxiv2022

Organization, genomic targeting and assembly of three distinct SWI/SNF chromatin remodeling complexes in Arabidopsis

Switch defective/sucrose non-fermentable (SWI/SNF) complexes are evolutionarily conserved multi-subunit machines that play vital roles in chromatin architecture regulation for modulating gene expression via sliding or ejection of nucleosomes in eukaryotes. In plants, perturbations of SWI/SNF subunits often result in severe developmental disorders. However, the subunit composition, pathways of assembly, and genomic targeting of the plant SWI/SNF complexes remain undefined. Here, we reveal the organization, genomic targeting and assembly of three distinct Arabidopsis SWI/SNF complexes: BRAHMA-Associated SWI/SNF complexes (BAS), SPLAYED-Associated SWI/SNF complexes (SAS) and MINUSCULE-Associated SWI/SNF complexes (MAS). We show that BAS complexes are equivalent to human ncBAF, whereas SAS and MAS complexes evolve in multiple subunits unique to plants, suggesting a plant-specific functional evolution of SWI/SNF complexes. We further demonstrate overlapping and specific genomic targeting of the three plant SWI/SNF complexes on chromatin and reveal that SAS complexes are necessary for the correct genomic localization of the BAS complexes. Finally, we define the role of core module subunit in the assembly of the plant SWI/SNF complexes and highlight that ATPase module subunit is required for global complex stability and the interaction of core module subunits in SAS and BAS complexes in Arabidopsis. Together, our work highlights the divergence of SWI/SNF chromatin remodelers during the eukaryote evolution and provides a comprehensive landscape for understanding the plant SWI/SNF complexes organization, assembly, genomic targeting, and function. One-sentence summaryComprehensively define the organization, genomic targeting and assembly of three distinct SWI/SNF chromatin remodeling complexes in Arabidopsis

plant biology↗

bioRxiv2022

DNA-caged Nanoparticles via Electrostatic Self-Assembly

DNA-modified nanoparticles enable DNA sensing and therapeutics in nanomedicine and are also crucial for nanoparticle self-assembly with DNA-based materials. However, methods to conjugate DNA to nanoparticle surfaces are limited, inefficient, and lack control. Inspired by DNA tile nanotechnology, we demonstrate a new approach to nanoparticle modification based on electrostatic attraction between negatively charged DNA tiles and positively charged nanoparticles. This approach does not disrupt nanoparticle surfaces and leverages the programmability of DNA nanotechnology to control DNA presentation. We demonstrated this approach using a variety of nanoparticles, including polymeric micelles, polystyrene beads, gold nanoparticles, and superparamagnetic iron oxide nanoparticles with sizes ranging from 5-20 nm in diameter. DNA cage formation was confirmed through transmission electron microscopy (TEM), neutralization of zeta potential, and a series of fluorescence experiments. DNA cages present "handle" sequences that can be used for reversible target attachment or self-assembly. Handle functionality was verified in solution, at the solid-liquid interface, and inside fixed cells, corresponding to applications in biosensing, DNA microarrays, and erasable immunocytochemistry. These experiments demonstrate the versatility of the electrostatic DNA caging approach and provide a new pathway to nanoparticle modification with DNA that will empower further applications of these materials in medicine and materials science.

bioengineering↗

bioRxiv2022

Styxl2 regulates de novo sarcomere assembly by binding to non-muscle myosin IIs and promoting their degradation

Styxl2, a poorly characterized pseudophosphatase, was identified as a transcriptional target of the Jak1-Stat1 pathway during myoblast differentiation in culture. Styxl2 is specifically expressed in vertebrate striated muscles. By gene knockdown or genetic knockout, we found that Styxl2 plays an essential role in maintaining sarcomere integrity in developing muscles of both zebrafish and mice. To further reveal the functions of Styxl2 in adult muscles, we generated two inducible knockout mouse models: one with Styxl2 being deleted in mature myofibers to assess its role in sarcomere maintenance, and the other in adult muscle satellite cells (MuSCs) to assess its role in de novo sarcomere assembly. We find that Styxl2 is not required for sarcomere maintenance but functions in de novo sarcomere assembly during injury-induced muscle regeneration. Mechanistically, Styxl2 interacts with non-muscle myosin IIs, enhances their ubiquitination, and targets them for autophagy-dependent degradation. Without Styxl2, the degradation of non-muscle myosin IIs is delayed, which leads to defective sarcomere assembly and force generation. Thus, Styxl2 promotes de novo sarcomere assembly by interacting with non-muscle myosin IIs and facilitating their autophagic degradation.

developmental biology↗