Biology subjects

Zhou, J.

Publications and source records attributed to Zhou, J..

At least 487 records · Page 27Linked to original sources

bioRxiv2021

SARS-CoV-2 hijacks neutralizing dimeric IgA for enhanced nasal infection and injury

Robust severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection in nasal turbinate (NT) accounts for high viral transmissibility, yet whether neutralizing IgA antibodies can control it remains unknown. Here, we evaluated receptor binding domain (RBD)-specific monomeric B8-mIgA1 and B8-mIgA2, and dimeric B8-dIgA1 and B8-dIgA2 against intranasal SARS-CoV-2 challenge in Syrian hamsters. These antibodies exhibited comparably potent neutralization against authentic virus by competing with human angiotensin converting enzyme-2 (ACE2) receptor for RBD binding. While reducing viruses in lungs, pre-exposure intranasal B8-dIgA1 or B8-dIgA2 led to 81-fold more infectious viruses and severer damage in NT than placebo. Virus-bound B8-dIgA1 and B8-dIgA2 could engage CD209 as an alternative receptor for entry into ACE2-negative cells and allowed viral cell-to-cell transmission. Cryo-EM revealed B8 as a class II neutralizing antibody binding trimeric RBDs in 3-up or 2-up/1-down conformation. Therefore, RBD-specific neutralizing dIgA engages an unexpected action for enhanced SARS-CoV-2 nasal infection and injury in Syrian hamsters.

microbiology↗

bioRxiv2021

Genome sequencing of white-blotched river stingray (Potamotrygon leopoldi) provides novel clues for niche-adaptation and skeleton formation

The white-blotched river stingray (Potamotrygon leopoldi) is a cartilaginous fish native to the Xingu River, a tributary of the Amazon River system. It possesses a lot of unique biological features such as disc-like body shape, bizarre color pattern and living in freshwater habitat while most stingrays and their close relatives are sea dwellers. As a member of the Potamotrygonidae family, P. leopoldi bears evolutionary signification in fish phylogeny, niche adaptation and skeleton formation. In this study, we present its draft genome of 4.11 Gb comprised of 16,227 contigs and 13,238 scaffolds, which has contig N50 of 3,937 kilobases and scaffold N50 of 5,675 kilobases in size. Our analysis shows that P. leopoldi is a slow-evolving fish, diverged from elephant shark about 96 million years ago. We find that two gene families related to immune system, immunoglobulin heavy constant delta genes, and T-cell receptor alpha/delta variable genes, stand out expanded in P. leopoldi only, suggesting robustness in response to freshwater pathogens in adapting novel environments. We also identified the Hox gene clusters in P. leopoldi and discovered that seven Hox genes shared by five representative fishes are missing in P. leopoldi. The RNA-seq data from P. leopoldi and other three fish species demonstrate that fishes have a more diversified tissue expression spectrum as compared to the corresponding mammalian data. Our functional studies suggest that the lack of genes encoding vitamin D-binding protein in cartilaginous (both P. leopoldi and Callorhinchus milii) fishes could partly explain the absence of hard bone in their endoskeleton. Overall, this genome resource provides new insights into the niche-adaptation, body plan and skeleton formation of P. leopoldi as well as the genome evolution in cartilaginous fish.

genomics↗

bioRxiv2021

SMC1A facilitates gastric cancer cells proliferation, migration and invasion via promoting SNAI2 activated EMT

Backgroundstructural maintenance of chromosomes protein 1A (SMC1A) is a crucial subunit of the cohesion protein complex and plays a vital role in cell cycle regulation, genomic stability maintenance, chromosome dynamics. Recent studies demonstrated that SMC1A participate in tumorigenesis. This reseach aims to explore the role and the underlying mechanisms of SMC1A in gastric cancer (GC). Materials and methodsRT-qPCR and western blot were used to examine the expression levels of SMC1A in GC tissues and cell lines. The role of SMC1A on GC cell proliferation, migration, invasion and epithelial-mesenchymal transition (EMT)were analyzed. Furthermore,the mechanism of SMC1A action was investigated. ResultsSMC1A was highly expressed in GC tissues and cell lines. The high expression of SMC1A indicated the poor overall survival of GC patients from Kaplan-Meier Plotter. Enhancing the expression of SMC1A in AGS remarkably promoted cell proliferation, migration and invasion. While knockdown of SMC1A in HCG27 inhibited cell proliferation, migration and invasion of HGC27 cells. Moreover, its observed that SMC1A promoted EMT and malignant cell behaviors via regulating SNAI2 Conclusionour study revealed SMC1A facilitates gastric cancer cell proliferation, migration and invasion via promoting SNAI2 activated EMT, which indicated SMC1A may be a potential target for gastric cancer therapy.

cancer biology↗

bioRxiv2021

Taxonomy Analysis in Bacteria Kingdom based onProtein Domain: A Comparison Study

The taxonomy research on the bacterial kingdom is important and can be usually conducted by the analysis on conserved genes, 16s rRNA, protein domain, and so on. Comparatively, the protein domains maintain a most direct relationship with phenotypes. In this paper, based on the protein domain, we propose a 3-step framework to standardize the classification process of bacteria. Different model candidates are involved and discussed in each step. By comparing the classification results with existing taxonomy, we select the most appropriate candidate to improve the framework, and furthermore, discuss their biological significance. Finally, we put forward taxonomy suggestions based on the best classification results. Significance StatementWe standardize a 3-step framework to carry out bacterial taxonomy research based on protein domain. Furthermore, we filter out the best solution in each step that can together generate the most appropriate classification result, and at the same time, we discuss the biological significant it indicates. Finally, we propose suggestions on NCBI bacterial taxonomy based on the classification results.

bioinformatics↗

bioRxiv2021

Regional Cell Atlas of Human Intestine Shapes Distinct Immune Surveillance

Regional intestinal immune surveillance remains obscure. In this study, we integrated single-cell RNA sequencing and spatial transcriptomics to create a regional atlas of fetal and adult intestines, consisting of 59 cell subsets, of which eight new subsets and ILCs transition states were identified. Results revealed that microenvironment determines in-situ cell differentiation and shapes the regional molecular characteristics, allowing different intestinal segments with diverse functions. We characterized the regional expression of mucins, immunoglobulins, and antimicrobial peptides (AMPs) and their shift during development and in inflammatory bowel disease. Notably, -defensins expressed most abundantly in small intestinal LGR5+ stem cells, rather than in Paneth cells, and down-regulated as cell maturing. Common upstream transcription factors controlled the AMPs expression, illuminating the concurrent change of AMPs during epithelial differentiation, and the spatial co-expression patterns. We demonstrated the correspondence of cell focus of risk genes to diseases location susceptibility and identified distinct cell-cell crosstalk and spatial heterogeneity of immune cell homing in different gut segments. Overall, a cross-spatiotemporal approach to transcriptomes at single-cell resolution revealed that the regional milieu of the human intestine determined cellular and molecular cues of immune surveillance, dictating gut homeostasis and disease.

cell biology↗

bioRxiv2021

Transferrin receptor 1-mediated iron uptake regulates bone mass in mice via osteoclast mitochondria and cytoskeleton

Increased intracellular iron spurs mitochondrial biogenesis and respiration to satisfy high-energy demand during osteoclast differentiation and bone-resorbing activities. Transferrin receptor 1 (TFR1) mediates cellular iron uptake through endocytosis of iron-loaded transferrin and its expression increases during osteoclast differentiation. Nonetheless, the precise functions of TFR1 and TFR1-mediated iron uptake in osteoclast biology and skeletal homeostasis remain incompletely understood. To investigate the role of TFR1 in osteoclast lineage cells, we conditionally deleted Tfr1 gene in myeloid precursors or mature osteoclasts by crossing Tfr1- floxed mice with LysM-Cre and Ctsk-Cre mice, respectively. Skeletal phenotyping by {micro}CT and histology unveiled that loss of Tfr1 in osteoclast progenitor cells resulted in a three-fold increase in trabecular bone mass in the long bones of 10-week old female but not male mice. Although high trabecular bone volume in long bones was seen in both male and female mice with deletion of Tfr1 in mature osteoclasts, this phenotype was more pronounced in female knockout mice. Mechanistically, disruption of Tfr1 expression attenuated mitochondrial metabolism and cytoskeletal organization in mature osteoclasts, leading to decreased bone resorption with no impact on osteoclastogenesis. These results indicate that Tfr1-mediated iron uptake is specifically required for osteoclast function and is indispensable for bone remodeling.

cell biology↗

bioRxiv2021

The gut microbial signature of gestational diabetes mellitus and the association with diet intervention

Gestational diabetes mellitus (GDM) is a high-risk pregnancy complication that is associated with metabolic disorder phenotypes, such as abnormal blood glucose and obesity. The link between microbiota and diet management contributes to metabolic homeostasis in GDM. Therefore, it is crucial to understand the structure of the gut microbiota in GDM and to explore the effect of dietary management on the microbiota structure. In this study, we analyzed the composition of the gut microbiota between 27 GDM and 30 healthy subjects at two time points using Illumina HiSeq 2500 platform. The taxonomy analyses suggested that the overall bacteria clustered by diabetes status, rather than diet intervention. Of particular interest, the phylum Acidobacteria in GDM was significantly increased, and positively correlated with blood glucose levels. Moreover, Partial least-squares discriminant analysis (PLS-DA) revealed that certain genera in the phyla Firmicutes, Bacteroidetes, Proteobacteria, and Lentisphaerae characterized the GDM gut microbiota. Correlation analysis indicated that blood glucose levels and BMI index were correlated with the relative abundance of SCFAS-producing genera. Through the comparison between the GDM and healthy samples with or without diet intervention, we discovered that the role of short-term diet management in GDM processes is associated with the change in the Firmicutes/Bacteroidetes ratio and some specific taxa, rather than an alternative gut microbial pattern. Our study have important implications for understanding the beneficial effects of diet intervention on the specific gut microbiota and thus possibly their metabolism in pregnant women with GDM. ImportanceUnderstanding the composition and dynamics of the gut microbiota in GDM women under diet intervention is important because there may be opportunities for preventive strategies. We examined the relationships between GDM gut microbiota at two times before and after the diet intervention during second trimester of pregnancy and clinical characteristics in cohort of GDM women. We found that short-term diet management in GDM processes is associated with changes in the Firmicutes/Bacteroidetes ratio and some specific taxa rather than an alternative gut microbial pattern. Our study highlights the importance of considering diet intervention as the rescue of microbial dysfunction of GDM disease and can serve as a strategy for early prevention in future study.

microbiology↗

bioRxiv2021

Three-dimensional microenvironment regulates gene expression, function, and tight junction dynamics of iPSC-derived blood-brain barrier microvessels

The blood-brain barrier (BBB) plays a pivotal role in brain health and disease. In the BBB, brain microvascular endothelial cells (BMECs) are connected by tight junctions which regulate paracellular transport, and express specialized transporter systems which regulate transcellular transport. However, existing in vitro models of the BBB display variable physiological accuracy across a wide range of characteristics including gene/protein expression and barrier function. Here, we use an isogenic family of fluorescently-labeled iPSC-derived BMEC-like cells (iBMECs) and brain pericyte-like cells (iPCs) within two-dimensional confluent monolayers (2D) and three-dimensional (3D) tissue-engineered microvessels to explore how 3D microenvironment regulates gene expression and function of the in vitro BBB. We show that 3D microenvironment (shear stress, cell-ECM interactions, and cylindrical geometry) increases BBB phenotype and endothelial identity, and alters angiogenic and cytokine responses in synergy with pericyte co-culture. Tissue-engineered microvessels incorporating junction-labeled iBMECs enable study of the real-time dynamics of tight junctions during homeostasis and in response to physical and chemical perturbations.

bioengineering↗

bioRxiv2021

A vimentin-targeting oral compound with host-directed antiviral and anti-inflammatory actions addresses multiple features of COVID-19 and related diseases

Damage in COVID-19 results from both the SARS-CoV-2 virus and its triggered overreactive host immune responses. Therapeutic agents that focus solely on reducing viral load or hyperinflammation fail to provide satisfying outcomes in all cases. Although viral and cellular factors have been extensively profiled to identify potential anti-COVID targets, new drugs with significant efficacy remain to be developed. Here, we report the potent preclinical efficacy of ALD-R491, a vimentin-targeting small molecule compound, in treating COVID-19 through its host-directed antiviral and anti-inflammatory actions. We found that by altering the physical properties of vimentin filaments, ALD-491 affected general cellular processes as well as specific cellular functions relevant to SARS-CoV-2 infection. Specifically, ALD-R491 reduced endocytosis, endosomal trafficking, and exosomal release, thus impeding the entry and egress of the virus; increased the microcidal capacity of macrophages, thus facilitating the pathogen clearance; and enhanced the activity of regulatory T cells, therefore suppressing the overreactive immune responses. In cultured cells, ALD-R491 potently inhibited the SARS-CoV-2 spike protein and human ACE2-mediated pseudoviral infection. In aged mice with ongoing, productive SARS-CoV-2 infection, ALD-R491 reduced disease symptoms as well as lung damage. In rats, ALD-R491 also reduced bleomycin-induced lung injury and fibrosis. Our results indicate a unique mechanism and significant therapeutic potential for ALD-R491 against COVID-19. We anticipate that ALD-R491, an oral, fast-acting, and non-toxic agent targeting the cellular protein with multipart actions, will be convenient, safe, and broadly effective, regardless of viral mutations, for patients with early- or late-stage disease, post-COVID complications and other related diseases. IMPORTANCEWith the Delta variant currently fueling a resurgence of new infections in the fully-vaccinated population, developing an effective therapeutic drug is especially critical and urgent in fighting COVID-19. In contrast to the many efforts to repurpose existing drugs or address only one aspect of COVID-19, we are developing a novel agent with first-in-class mechanism-of-actions that address both the viral infection and the overactive immune system in the pathogenesis of the disease. Unlike virus-directed therapeutics that may lose efficacy due to viral mutations and immunosuppressants that require ideal timing to be effective, this agent, with its unique host-directed antiviral and anti-inflammatory actions, can work against all variants of the virus, be effective during all stages of the disease, and even resolve post-disease damage and complications. A further development of the compound will provide an important tool in the fight against COVID-19, its complications, as well as future outbreaks of new viruses.

pharmacology and toxicology↗

bioRxiv2021

A Recurring Chemogenetic Switch for Chimeric Antigen Receptor T Cells

As a revolutionary cancer treatment, the chimeric antigen receptor (CAR) T cell therapy suffers from complications such as cytokine release syndromes and T cell exhaustion. Their mitigation desires controllable activation of CAR-T cells that is achievable through regulatory display of CARs on the T cell surface. By embedding the hepatitis C virus NS3 protease (HCV-NS3) in an anti-CD19 CAR between the anti-CD19 single-chain variable fragment (scFv) and the hinge domain, we showed that the display of anti-CD19 scFv on CAR-T cells was positively correlated to the presence of a clinical HCV-NS3 inhibitor asunaprevir (ASV). This novel CAR design that allows the display of anti- CD19 scFv on the T cell surface in the presence of ASV and its removal in the absence of ASV effectuates a practically recurring chemical switch for CAR-T cells. We demonstrated that the intact CAR on T cells was repeatedly turn on and off by controlling the presence of ASV. The dose dependent manner of the intact CAR display on T cells with regard to the ASV concentration enables delicate modulation of CAR-T cell activation during cancer treatment. In a mouse model, we showed different treatment prospects when ASV was provided at different doses to mice that were infused with both human CD19+ lymphoma and the switchable CAR-T cells.

bioengineering↗

bioRxiv2021

Spectral fiber-photometry derives hemoglobin-absorption changes for accurate measurement of fluorescent sensors

Fiber-photometry is an emerging technique for recording fluorescent sensor activity in the brain. However, significant hemoglobin-absorption artifacts in fiber-photometry data may be misinterpreted as sensor activity changes. Because hemoglobin exists in nearly every location in the brain and its concentration varies over time, such artifacts could impede the accuracy of many photometry recording results. Here we present a novel use of spectral photometry technique and propose computational methods to quantify photon absorption effects by using activity-independent fluorescence signals, which can be used to derive oxy- and deoxy-hemoglobin concentration changes. Following time-locked neuronal activation in vivo, we observed that a 20% increase in CBV contributes to about a 4% decrease in green fluorescence signal and a 2% decrease in red fluorescence signal. While these hemoglobin concentration changes are often temporally delayed than the fast-responding fluorescence spikes, we found that erroneous interpretation may occur when examining pharmacology-induced sustained activity changes, and in some cases, hemoglobin-absorption could flip the GCaMP signal polarity. We provided hemoglobin-based correction methods to restore fluorescence signals across spectra and compare our results against the commonly used regression approach. We also demonstrated the utility of spectral fiber-photometry for delineating brain regional differences in hemodynamic response functions. HighlightsO_LIHemoglobin-absorption compromises fiber-photometry recording in vivo C_LIO_LISpectral photometry allows quantification of hemoglobin concentration changes for correction C_LIO_LIThe proposed platform allows measuring regional differences in neurovascular transfer function C_LI

neuroscience↗

bioRxiv2021

Mutations that adapt SARS-CoV-2 to mustelid hosts do not increase fitness in the human airway.

SARS-CoV-2 has a broad mammalian species tropism infecting humans, cats, dogs and farmed mink. Since the start of the 2019 pandemic several reverse zoonotic outbreaks of SARS-CoV-2 have occurred in mink, one of which reinfected humans and caused a cluster of infections in Denmark. Here we investigate the molecular basis of mink and ferret adaptation and demonstrate the spike mutations Y453F, F486L, and N501T all specifically adapt SARS-CoV-2 to use mustelid ACE2. Furthermore, we risk assess these mutations and conclude mink-adapted viruses are unlikely to pose an increased threat to humans, as Y453F attenuates the virus replication in human cells and all 3 mink-adaptations have minimal antigenic impact. Finally, we show that certain SARS-CoV-2 variants emerging from circulation in humans may naturally have a greater propensity to infect mustelid hosts and therefore these species should continue to be surveyed for reverse zoonotic infections.

microbiology↗

bioRxiv2021

A bacterial genome and culture collection of gut microbial in weanling piglet

The microbiota hosted in the pig gastrointestinal tract are important for productivity of livestock. However, the individual species and functional repertoires that make up the pig gut microbiome remain largely undefined. Here we comprehensively investigated the genomes and functions of the piglet gut microbiome using culture-based and metagenomics approaches. A collection included 266 cultured genomes and 482 metagenome-assembled genomes (MAGs) that were clustered to 428 species across 10 phyla was established. Among these clustered species, 333 genomes represent potential new species. Less matches between cultured genomes and MAGs revealed a substantial bias for the acquisition of reference genomes by the two strategies. Glycoside hydrolases was the dominant category of carbohydrate-active enzymes. 445 secondary metabolite biosynthetic genes were predicted from 292 genomes with bacteriocin being the most. Pan genome analysis of Limosilactobacillus reuteri uncover the biosynthesis of reuterin was strain-specific and the production was experimentally determined. These genomic resources will enable a comprehensive characterization of the microbiome composition and function of pig gut.

microbiology↗

bioRxiv2021

A toolbox for studying cortical physiology in primates

Lesioning and neurophysiological studies have facilitated the elucidation of cortical functions and mechanisms of functional recovery following injury. Clinical translation of such studies is contingent on their employment in non-human primates (NHPs), yet tools for monitoring and modulating cortical physiology are incompatible with conventional NHP lesioning techniques. To address these challenges, we developed a toolbox demonstrated in seven macaques. We introduce the photothrombotic method to induce focal cortical lesions alongside a quantitative model for the design of lesion profiles based on experimental needs. Large-scale ([~]5 cm2) vascular and neural dynamics can be monitored and lesion induction can be validated in vivo with optical coherence tomography angiography and our electrocorticographic array, the latter of which also enables testing stimulation-based interventions. By combining optical and electrophysiological techniques in NHPs, we can enhance our understanding of cortical functions, investigate functional recovery mechanisms, integrate physiological and behavioral findings, and develop treatments for neurological disorders.

neuroscience↗

bioRxiv2021

Postnatal SETD1B is essential for learning and the regulation of neuronal plasticity genes

Histone 3 lysine 4 methylation (H3K4me) is mediated by six different lysine methyltransferases. Amongst these enzymes SET domain containing 1b (SETD1B) has been linked to syndromic intellectual disability but its role in the postnatal brain has not been studied yet. Here we employ mice that lack Setd1b from excitatory neurons of the postnatal forebrain and combine neuron-specific ChIP-seq and RNA-seq approaches to elucidate its role in neuronal gene expression. We observe that SETD1B controls the expression of genes with a broad H3K4me3 peak at their promoters that represent neuronal enriched genes linked to learning and memory function. Comparative analysis to corresponding data from conditional Kmt2a and Kmt2b knockout mice suggests that this function is specific to SETD1B. Moreover, postnatal loss of Setd1b leads to severe learning impairment, suggesting that SETD1B-mediated regulation of H3K4me levels in postnatal neurons is critical for cognitive function.

neuroscience↗

bioRxiv2021

A sequence-based global map of regulatory activity for deciphering human genetics

Sequence is at the basis of how the genome shapes chromatin organization, regulates gene expression, and impacts traits and diseases. Epigenomic profiling efforts have enabled large-scale identification of regulatory elements, yet we still lack a sequence-based map to systematically identify regulatory activities from any sequence, which is necessary for predicting the effects of any variant on these activities. We address this challenge with Sei, a new framework for integrating human genetics data with sequence information to discover the regulatory basis of traits and diseases. Our framework systematically learns a vocabulary for the regulatory activities of sequences, which we call sequence classes, using a new deep learning model that predicts a compendium of 21,907 chromatin profiles across >1,300 cell lines and tissues, the most comprehensive to-date. Sequence classes allow for a global view of sequence and variant effects by quantifying diverse regulatory activities, such as loss or gain of cell-type-specific enhancer function. We show that sequence class predictions are supported by experimental data, including tissue-specific gene expression, expression QTLs, and evolutionary constraints based on population allele frequencies. Finally, we applied our framework to human genetics data. Sequence classes uniquely provide a non-overlapping partitioning of GWAS heritability by tissue-specific regulatory activity categories, which we use to characterize the regulatory architecture of 47 traits and diseases from UK Biobank. Furthermore, the predicted loss or gain of sequence class activities suggest specific mechanistic hypotheses for individual regulatory pathogenic mutations. We provide this framework as a resource to further elucidate the sequence basis of human health and disease.

genomics↗

bioRxiv2021

B Cell Receptor Signaling Drives APOBEC3 Expression Via Direct Enhancer Regulation in Chronic Lymphocytic Leukemia B Cells

Constitutively activated B cell receptor (BCR) signaling is a primary biological feature of chronic lymphocytic leukemia (CLL). The biological events controlled by BCR signaling in CLL are not fully understood and need investigation. To make inroads we obtained blood samples from CLL patients before and after Brutons tyrosine kinase inhibitors (BTKi) treatment and used them to study BCR signaling regulated genes. Here, by analysis of the chromatin states and gene expression profiles of CLL B cells from patients before and after BTKi ibrutinib treatment, we show that BTKi treatment leads to a decreased expression of APOBEC3 family genes in an enhancer regulation dependent manner. BTKi treatment reduces enrichment of enhancer markers (H3K4me1, H3K27ac) and chromatin accessibility at putative APOBEC3 enhancers. CRISPR-Cas9 directed deletion or inhibition of the putative APOBEC3 enhancers leads to reduced APOBEC3 expression. We further find that transcription factor NFATc1 couples BCR signaling with the APOBEC3 enhancer activity to control APOBEC3 expression. Importantly, enhancer regulated APOBEC3 expression contributes to replication stress in malignant B cells. We also demonstrate a novel mechanism for BTKi suppression of APOBEC3 expression via direct enhancer regulation in a NFATc1 dependent manner, implicating BCR signaling as a potential regulator of leukemic genomic instability. Key pointsO_LIBCR signaling pathway regulates APOBEC3 expression via direct enhancer regulation. C_LIO_LIAOPEBC3 enhancers are involved in the process of DNA replication stress, implicating a potential role in B cell genomic instability and CLL evolution C_LI

cancer biology↗

bioRxiv2021

Evolution of a chordate-specific mechanism for myoblast fusion

The size of an animal is determined by the size of its musculoskeletal system. Myoblast fusion is an innovative mechanism that allows for multinucleated muscle fibers to compound the size and strength of individual mononucleated cells. However, the evolutionary history of the control mechanism underlying this important process is currently unknown. The phylum Chordata hosts closely related groups that span distinct myoblast fusion states: no fusion in cephalochordates, restricted fusion and multinucleation in tunicates, and extensive, obligatory fusion in vertebrates. To elucidate how these differences may have evolved, we studied the evolutionary origins and function of membrane-coalescing agents Myomaker and Myomixer in various groups of chordates. Here we report that Myomaker likely arose through gene duplication in the last common ancestor of tunicates and vertebrates, while Myomixer appears to have evolved de novo in early vertebrates. Functional tests revealed an unexpectedly complex evolutionary history of myoblast fusion in chordates. A pre-vertebrate phase of muscle multinucleation driven by Myomaker was followed by the later emergence of Myomixer that enables the highly efficient fusion system of vertebrates. Thus, our findings reveal the evolutionary origins of chordate-specific fusogens and illustrate how new genes can shape the emergence of novel morphogenetic traits and mechanisms.

developmental biology↗