Biology subjects

Zhao, H.

Publications and source records attributed to Zhao, H..

At least 397 records · Page 22Linked to original sources

bioRxiv2022

APE1 recruits ATRIP to ssDNA in an RPA-independent manner to promote the ATR DNA damage response

Cells have evolved the DNA damage response (DDR) pathways in response to DNA replication stress or DNA damage. In the ATR-Chk1 DDR pathway, it has been proposed that ATR is recruited to RPA-coated single-strand DNA (ssDNA) by direct ATRIP-RPA interaction. However, it remains elusive whether and how ATRIP is recruited to ssDNA in an RPA-independent manner. Here, we provide evidence that APE1 directly associates ssDNA to recruit ATRIP onto ssDNA in an RPA-independent fashion. The N-terminal motif within APE1 is required and sufficient for the APE1-ATRIP interaction in vitro and the distinct APE1-ATRIP interaction is required for ATRIP recruitment to ssDNA and the ATR-Chk1 DDR pathway activation in Xenopus egg extracts. In addition, APE1 directly associates with RPA70 and RPA32 via two distinct motifs. Taken together, our evidence identifies APE1 as a direct recruiter of ATRIP onto ssDNA independent of RPA in the activation of ATR DDR pathway. SummaryO_LIAPE1 associates with ssDNA and ATRIP directly via distinct motifs and thereby recruits ATRIP onto ssDNA independent of RPA to promote the ATR DDR. C_LIO_LIAPE1 interacts with RPA via distinct two motifs in vitro but such RPA-APE1 interaction is dispensable for ATRIP recruitment onto ssDNA. C_LI

molecular biology↗

bioRxiv2022

Proteome capacity constraints favor respiratory ATP generation

Cells face competing metabolic demands. These include efficient use of both limited substrates and limited proteome capacity, as well as flexibility to deal with different environments. Flexibility requires spare enzyme capacity, which is proteome inefficient. ATP generation can occur via fermentation or respiration. Fermentation is much less substrate-efficient, but often assumed to be more proteome efficient 1-3, thereby favoring fast-growing cells engaging in aerobic glycolysis 4-8. Here, however, we show that mitochondrial respiration is actually more proteome-efficient than aerobic glycolysis. Instead, aerobic glycolysis arises from cells maintaining the flexibility to grow also anaerobically. These conclusions emerged from an unbiased assessment of metabolic regulatory mechanisms, integrating quantitative metabolomics, proteomics, and fluxomics, of two budding yeasts, Saccharomyces cerevisiae and Issatchenkia orientalis, the former more fermentative and the latter respiratory. Their energy pathway usage is largely explained by differences in proteome allocation. Each organisms proteome allocation is remarkably stable across environmental conditions, with metabolic fluxes predominantly regulated at the level of metabolite concentrations. This leaves extensive spare biosynthetic capacity during slow growth and spare capacity of their preferred bioenergetic machinery when it is not essential. The greater proteome-efficiency of respiration is also observed in mammals, with aerobic glycolysis occurring in yeast or mammalian cells that maintain a fermentation-capable proteome conducive to both aerobic and anaerobic growth.

systems biology↗

bioRxiv2022

Matrix-seq: An adjustable-resolution spatial transcriptomics via microfluidic matrix-based barcoding.

Spatial transcriptomics technology complements the spatial information lost in single-cell RNA sequencing, which enables visualization and quantitative analysis of transcriptomics of cells in tissue sections. Although this technology is a promising tool to study complex biological processes, its popularization is limited by cumbersome barcoding steps. We presented a microfluidics-based barcoding strategy called Matrix-seq, which gets rid of both precision instruments and the in situ indexing. The deterministic barcoding matrix is fabricated by the crossflow of Barcode-X and Barcode-Y. The overlapping areas (spot) formed deterministic barcoding primers (Barcode-X-Y) via the ligation reaction. Matrices with different spot size (ranging from 10 to 50 m), which was decided by the width of microchannels, were fabricated and then applied to a mouse main olfactory bulb section and a mouse brain section. While maintaining high performance and resolution, this technology greatly reduces the technical threshold and cost of spatial barcoding. As a result, Matrix-seq can be rapidly applied in various fields including developmental biology, neuroscience and clinical pathology. TeaserMatrix-seq provides an orthogonal microchannel-based barcoding strategy for adjustable-resolution spatial transcriptomics.

bioengineering↗

bioRxiv2022

The fitness landscape of the mobilized colistin resistance gene mcr-1

The emergence and global discovery of the mobilized colistin resistance gene, mcr-1, limits the clinical effectiveness of colistin as last-resort antibiotic against multiple-drug resistant bacteria. Although MCR-1 exhibits low levels of colistin resistance in E. coli, it is currently unknown whether mcr-1 may potentially evolve a high level of colistin resistance in the future. Here, we generated mcr-1 mutant library that included 27,965 variants, covering 94.44% of the single-nucleotide mutations. We quantified the relative growth of these variant strains under colistin exposure. Notably, most mutations in the catalytic domain, but not in the transmembrane domain, reduce colistin resistance. The structural basis for the mutational effects revealed that the transmembrane domain may contribute to MCR-1 evolution. Altogether, our data shed light on the prediction of MCR-1 evolution, which could be useful for designing novel treatment strategies.

evolutionary biology↗

bioRxiv2022

Analysis of the mechanism of castor tolerance to Cd metal based on proteomics and metabolomics

The pollution of soil with heavy metals is an increasingly serious worldwide problem, and cadmium (Cd) has attracted attention because of its high toxicity to almost all plants. Since castor tolerates the accumulation of heavy metals, it has the potential for heavy metal soil remediation. We studied the mechanism of the tolerance of castor to Cd stress treatments at three doses: 300 mg/L, 700 mg/L, and 1,000 mg/L. Our research provides new ideas for revealing the defense and detoxification mechanisms of Cd-stressed castor. By combining the results of physiology, differential proteomics and comparative metabolomics, we conducted a comprehensive analysis of the networks that regulate the response of castor to Cd stress. The physiological results mainly emphasize the super-sensitive responses of castor plant roots to Cd stress and the effects of Cd stress on plants antioxidant system, ATP synthesis and ion homeostasis. We confirmed these results at the protein and metabolite levels. At the same time, proteomics and metabolomics show that castor plants mainly block the root systems absorption of Cd2+ by enhancing the strength of the cell wall, and inducing programmed cell death in response to the three different doses of Cd stress. In addition, the plasma membrane ATPase encoding gene (RcHA4), which was significantly upregulated in our differential proteomics and RT-qPCR studies, was transgenically overexpressed in wild type Arabidopsis thaliana for functional verification. The results indicated that this gene plays an important role in improving plant Cd tolerance.

molecular biology↗

bioRxiv2022

Outline and divergence time of subkingdom Mucoromyceta: two new phyla, five new orders, six new families and seventy-three new species

Zygomycetes are phylogenetically early diverged, ecologically diverse, industrially valuable, agriculturally beneficial, and clinically pathogenic fungi. Although new phyla and subphyla have been constantly established to accommodate specific members and a subkingdom, Mucoromyceta, was erected to unite core zygomycetous fungi, their phylogenetic relationships have not been well resolved. Taking account of the information of monophyly and divergence time estimated from ITS and LSU rDNA sequences, the present study updates the classification framework of the subkingdom Mucoromyceta from the phylum down to the generic rank: six phyla (including two new phyla Endogonomycota and Umbelopsidomycota), eight classes, 15 orders (including five new orders Claroideoglomerales, Cunninghamellales, Lentamycetales, Phycomycetales and Syncephalastrales), 41 families (including six new families Circinellaceae, Gongronellaceae, Protomycocladaceae, Rhizomucoraceae, Syzygitaceae and Thermomucoraceae), and 121 genera. The taxonomic hierarchy was calibrated with estimated divergence times: phyla 810-639 Mya, classes 651-585 Mya, orders 570-400 Mya, and families 488-107 Mya. Along with this outline, 71 genera are annotated and 73 new species are described. In addition, three new combinations are proposed. In this paper, we update the taxonomic backbone of the subkingdom Mucoromyceta and reinforce its phylogeny. We also contribute numerous new taxa and enrich the diversity of Mucoromyceta.

microbiology↗

bioRxiv2022

Aging-related iron deposit prevents the benefits of HRT from late postmenopausal atherosclerosis

Postmenopausal atherosclerosis has been attributed to estrogen deficiency. The beneficial effect of hormone replacement therapy (HRT), however, is lost in late postmenopausal women with atherogenesis. We asked whether aging-related iron accumulation affects estrogen receptor (ER) expression explaining HRT inefficacy. A negative correlation between aging-related systemic iron deposition and ER expression in postmenopausal AS patients was established. In an ovariectomized ApoE-/- mouse model, estradiol treatment had contrasting effects on ER expression in early versus late postmenopausal mice. ER expression was inhibited by iron treatment in cell culture and iron-overloaded mice. Combined treatment with estradiol and iron further decreased ER expression, mediated by iron-regulated E3 ligase Mdm2. In line with these observations, cellular cholesterol efflux was reduced and endothelial homeostasis was disrupted and, consequently, atherosclerosis was aggravated. Accordingly, systemic iron chelation attenuated estradiol-triggered progressive atherosclerosis in late postmenopausal mice. Thus, iron and estradiol together downregulate ER through Mdm2-mediated proteolysis, explaining failures of HRT in late postmenopausal subjects with aging-related iron accumulation. HRT is recommended immediately after menopause along with appropriate iron chelation to protect from atherosclerosis.

cell biology↗

bioRxiv2022

AIM1-dependent high basal SA accumulation modulates stomatal aperture in rice

The basal levels of salicylic acid (SA), an important plant hormone, vary dramatically among plant species. In the shoot, for example, the monocot plant rice contains almost 100 times higher SA levels than the dicot model plant Arabidopsis. Despite its high basal levels, neither the biosynthetic pathway nor the biological functions of SA is well understood in rice. Here, we report that the synthesis of basal SA in rice shoot is not altered in the mutant for the ISOCHORISMATE SYNTHASE (ICS) gene, but drastically reduced in the mutant for OsAIM1, which encodes a beta-oxidation enzyme in the phenylalanine ammonia-lyase (PAL) pathway. Analogous to its role in thermogenesis, compromised SA accumulation in the Osaim1 mutant led to a lower shoot temperature than wild-type plants. However, this shoot temperature defect was resulted from increased transpiration due to elevated steady-state stomatal aperture in the mutant. Furthermore, the high basal shoot SA level is required for sustained expression of WRKY45 to modulate the steady-state stomatal aperture and shoot temperature in rice. Taken together, these results provide the direct genetic evidence for the critical role of the PAL pathway in the biosynthesis of high levels of basal SA, which play an important role in the regulation of steady-state stomatal aperture to promote fitness under both normal and stress conditions.

plant biology↗

bioRxiv2022

Multiple lineages of Monkeypox virus detected in the United States, 2021-2022

Monkeypox is a viral zoonotic disease endemic in Central and West Africa. In May 2022, dozens of non-endemic countries reported hundreds of monkeypox cases, most with no epidemiological link to Africa. We identified two lineages of Monkeypox virus (MPXV) among nine 2021 and 2022 U.S. monkeypox cases. A 2021 case was highly similar to the 2022 MPXV outbreak variant, suggesting a common ancestor. Analysis of mutations among these two lineages revealed an extreme preference for GA-to-AA mutations indicative of APOBEC3 cytosine deaminase activity that was shared among West African MPXV since 2017 but absent from Congo Basin lineages. Poxviruses are not thought to be subject to APOBEC3 editing; however, these findings suggest APOBEC3 activity has been recurrent and dominant in recent West African MPXV evolution.

genomics↗

bioRxiv2022

Multiplex CRISPR strategy targeting viral genome for agriculture and clinical use

African Swine Fever (ASF) is a viral disease with exceptionally high lethality in domestic pigs and wild boar worldwide1, 2, without any effective vaccine or drug to prevent its spread. In this study, we established a multiplexable CRISPR-Cas-gRNA system targeting 13 genomic loci in the ASF virus genome that could prevent viral replication by cutting its genome. Furthermore, we generated pig strains expressing the multiplexable CRISPR-Cas-gRNA via germline genome editing and demonstrated that the gene-edited pigs were more resistant to ASFV infection and less likely to spread the virus upon infection. As far as we know, our study presents the first living organism generated via germline editing to demonstrate resistance to viral infection via CRISPR-Cas. We anticipate our work to be helpful for both agricultural and biomedical applications, such as xenotransplantation.

bioengineering↗

bioRxiv2022

Transcriptome analysis of human preimplantation embryo reveals expressed waves associated with blastulation failure based on embryonic grade and age

In the in vitro fertilization and embryo transfer (IVF-ET) treatments, blastocyst culture is the method of choice for the generation of the embryos. Blastocysts can present different growth, quality, availability, and morphological characteristics that can be used to evaluate them. Although extreme blastocyst formation failures have been associated with the alteration of a single gene, the molecular factors responsible for arrested embryos remain unknown. RNA-sequencing (RNA-seq) is a promising tool for facilitating transcriptomic studies in early human embryos, thus allowing the investigation of gene expression discrepancies associated with different morphological criteria. Herein, we performed transcriptome analyses of the different stages of arrested human embryos. We identified candidate genes and related cell signaling pathways potentially associated with either arrested or developed embryos. Specifically, the three genes (MOV10L1, DDX4, and FKBP6) related to both DNA methylation and piRNA metabolic pathway might be involved in embryo development. Additionally, the transcriptome of arrested early blastocysts was significantly different from developed late blastocysts. Although the gene expression profiles identified were not significantly different between low- and high-quality late blastocysts, a significant difference in the profiles of day 5 and day 6 available late blastocysts was observed, which may be related to the clinical pregnancy rate associated with IVF-ET. Furthermore, we show that some chimeric RNAs may be functional in blastocyst development. Our findings uncovered new molecular markers that can be used for embryonic development detection, which might act as a tool for blastocyst selection for subsequent transfer.

genomics↗

bioRxiv2022

Alignment-free metal ion-binding site prediction from protein sequence through pretrained language model and multi-task learning

More than one-third of the proteins contain metal ions in the Protein Data Bank. Correct identification of metal ion-binding residues is important for understanding protein functions and designing novel drugs. Due to the small size and high versatility of metal ions, it remains challenging to computationally predict their binding sites from protein sequence. Existing sequence-based methods are of low accuracy due to the lack of structural information, and time-consuming owing to the usage of multi-sequence alignment. Here, we propose LMetalSite, an alignment-free sequence-based predictor for binding sites of the four most frequently seen metal ions (Zn2+, Ca2+, Mg2+ and Mn2+). LMetalSite leverages the pretrained language model to rapidly generate informative sequence representations and employs transformer to capture long-range dependencies. Multi-task learning is adopted to compensate for the scarcity of training data and capture the intrinsic similarities between different metal ions. LMetalSite was shown to surpass state-of-the-art structure-based methods by more than 19.7%, 14.4%, 36.8%, and 12.6% in AUPR on the four independent tests, respectively. Further analyses indicated that the self-attention modules are effective to learn the structural contexts of residues from protein sequence.

bioinformatics↗

bioRxiv2022

Novel tumorigenic FOXM1-PTAFR-PTAF axis revealed by multi-omic profiling in TP53/CDKN2A-double knockout human gastroesophageal junction organoid model

Inactivation of the tumor suppressor genes TP53 and CDKN2A occurs early during gastroesophageal junction (GEJ) tumorigenesis. However, due to a paucity of GEJ-specific disease models, cancer-promoting consequences of TP53 and CDKN2A inactivation at the GEJ have been incompletely characterized. Here we report the development of the first wild-type primary human GEJ organoid model, as well as a CRISPR-edited transformed GEJ organoid model. CRISPR/Cas9 engineering to inactivate TP53 and CDKN2A (TP53/CDKN2AKO) in GEJ organoids induced morphologic dysplasia as well as pro-neoplastic features in vitro and tumor formation in vivo. Notably, lipidomic profiling identified several Platelet-Activating Factors (PTAFs) among the most upregulated lipids in CRISPR-edited organoids; and importantly, PTAF/PTAFR abrogation by siRNA knockdown or a pharmacologic inhibitor (WEB2086) significantly blocked proliferation and other pro-neoplastic features of TP53/CDKN2AKO GEJ organoids in vitro and tumor formation in vivo. In addition, murine xenografts derived from Eso26, an established esophageal adenocarcinoma (EAC) cell line, were suppressed by WEB2086. Mechanistically, TP53/CDKN2A dual inactivation disrupted both the transcriptome and the DNA methylome, likely mediated by key transcription factors, particularly Forkhead Box M1 (FOXM1). Importantly, FOXM1 activated PTAFR transcription by binding to the PTAFR promoter, further amplifying the PTAF-PTAFR pathway. In summary, we established a robust model system for investigating early GEJ neoplastic events, identified crucial metabolic and epigenomic changes occurring during GEJ model tumorigenesis, and discovered a potential cancer-therapeutic strategy, while providing insights into pro-neoplastic mechanisms associated with TP53/CDKN2A inactivation in early GEJ neoplasia. One Sentence SummaryNovel tumorigenic FOXM1-PTAFR-PTAF axis revealed by multi-omic profiling in TP53/CDKN2A-double knockout human gastroesophageal junction organoid model. Graphic Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=172 SRC="FIGDIR/small/491356v1_ufig1.gif" ALT="Figure 1"> View larger version (27K): org.highwire.dtl.DTLVardef@18dcb8dorg.highwire.dtl.DTLVardef@2ec0d6org.highwire.dtl.DTLVardef@17622b8org.highwire.dtl.DTLVardef@e184bc_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

bioRxiv2022

Simultaneous and sequential multi-species coronavirus vaccination

Although successful COVID-19 vaccines have been developed, multiple pathogenic coronavirus species exist, urging for development of multi-species coronavirus vaccines. Here we developed prototype LNP-mRNA vaccine candidates against SARS-CoV-2 (Delta variant), SARS-CoV and MERS-CoV, and test how multiplexing of these LNP-mRNAs can induce effective immune responses in animal models. A triplex scheme of LNP-mRNA vaccination induced antigen-specific antibody responses against SARS-CoV-2, SARS-CoV and MERS-CoV, with a relatively weaker MERS-CoV response in this setting. Single cell RNA-seq profiled the global systemic immune repertoires and the respective transcriptome signatures of multiplexed vaccinated animals, which revealed a systemic increase in activated B cells, as well as differential gene expression signatures across major adaptive immune cells. Sequential vaccination showed potent antibody responses against all three species, significantly stronger than simultaneous vaccination in mixture. These data demonstrated the feasibility, antibody responses and single cell immune profiles of multi-species coronavirus vaccination. The direct comparison between simultaneous and sequential vaccination offers insights on optimization of vaccination schedules to provide broad and potent antibody immunity against three major pathogenic coronavirus species. One sentence summaryMultiplexed mRNA vaccination in simultaneous and sequential modes provide broad and potent immunity against pathogenic coronavirus species.

immunology↗

bioRxiv2022

HSP90.6 is involved in grain filling via carbon and nitrogen metabolism in maize.

Carbon and nitrogen are the two most abundant nutrients in all living things, and their metabolism maintains normal plant growth. However, the molecular mechanism underlying carbon and nitrogen metabolism remains largely unknown. Here, we found that HSP90.6 is involved in the metabolism of carbon and nitrogen. We performed gene cloning and functional characterization of a maize EMS mutant ehsp90.6, whose kernels were small. HSP90.6 encodes heat shock protein 90.6, which has a single-amino acid mutation within its HATPase_c domain. Transcriptome profiling showed that the expression of amino acid biosynthesis- and carbon metabolism-related genes was significantly downregulated in hsp90.6. HSP90.6 is involved in the 26S proteasome degradation pathway, which affects nitrogen recycling to regulate amino acid synthesis; this occurs by interactions between HSP90.6 and the 26S proteasome subunits RPN6 and PBD2 (PRC2). The loss of HSP90.6 significantly reduced the activity of the 26S proteasome, resulting in the accumulation of ubiquitinated proteins and defects in nitrogen recycling. Moreover, HSP90.6 interacted with the 14-3-3 protein GF14-6 to participate in carbon metabolism. Together, these findings revealed that HSP90.6 regulates nutrient metabolism in maize seeds by affecting 26S proteasome-mediated nitrogen recycling and GF14-6-mediated carbon metabolism. One sentence summaryHSP90.6 is involved in nutrient metabolism via 26S proteasome-mediated protein degradation to promote nitrogen recycling and GF14-6 protein-mediated carbon metabolism. The author responsible for the distribution of materials integral to the findings presented in this article in accordance with the policy described in the Instructions for Authors (https://academic.oup.com/plcell/pages/General-Instructions) is Weibin Song (songwb@cau.edu.cn). HighlightsO_LIHATPase_c is necessary for HSP90.6 to regulate maize kernel development. C_LIO_LIHSP90.6 is involved in nitrogen recycling via the 26S proteasome degradation pathway. C_LIO_LIHSP90.6 interacts with the 14-3-3 protein GF14-6 to affect carbon metabolism. C_LI IN A NUTSHELLO_ST_ABSBackgroundC_ST_ABSSeeds are the main harvested organs of maize. Understanding the regulatory mechanism of grain filling is helpful to cultivate high-quality and high-yield maize. In the past few years, the regulatory network of grain filling has been explored through multiple means, including transcriptomic, proteomic and functional genomic techniques. Many genes that control grain filling through different mechanisms have been cloned, such as CTLP1 (Choline Transporter-like Protein 1), OS1 (Opaque Endosperm and Small Germ 1), and MN6 (Miniature Seed6). To identify new genes involved in maize grain filling, ethyl methanesulfonate (EMS) was used to induce mutations, and the ehsp90.6 mutant, which exhibited abnormal kernel development, was isolated by bulked segregant analysis RNA sequencing (BSR). QuestionWhy does the single-amino acid mutation of HSP90.6 affect grain size, and how does the loss of HSP90.6 affect grain filling? FindingsA single-amino acid mutant (ehsp90.6) and knockout mutant (hsp90.6) were obtained. We found that HSP90-6 was involved in the regulation of maize grain filling. A single-single amino acid mutation in the HATPase_c domain reduced the ATPase activity of HSP90.6, resulting in smaller grains. The functional loss of HSP90.6 resulted in the expression of amino acid biosynthesis- and carbon metabolism-related genes being significantly downregulated in hsp90.6. We indicated that HSP90.6 is involved in the 26S proteasome degradation pathway, which affects nitrogen recycling to regulate amino acid synthesis by interacting with the 26S proteasome subunits RPN6 and PBD2 (PRC2). Moreover, HSP90.6 was found to interact with the 14-3-3 protein GF14-6 to participate in carbon metabolism. Next stepsTo further verify that the interaction between HSP90.6 and 26S proteasome subunits and GF14-6 affects grain filling, knockout validation of RPN6, PBD2 (PRC2) and GF14-6 will be performed. In addition, since GF14-6 interacts with the phosphorylated proteins, we will determine the phosphorylation site of HSP90.6. Due to the important role of HSP90 family proteins in plant development, there are other regulatory pathways that need to be explored.

plant biology↗

bioRxiv2022

OTTERS: A powerful TWAS framework leveraging summary-level reference data

Most existing TWAS tools require individual-level eQTL reference data and thus are not applicable to summary-level reference eQTL datasets. The development of TWAS methods that can harness summary-level reference data is valuable to enable TWAS in broader settings and enhance power due to increased reference sample size. Thus, we develop a TWAS framework called OTTERS (Omnibus Transcriptome Test using Expression Reference Summary data) that adapts multiple polygenic risk score (PRS) methods to estimate eQTL weights from summary-level eQTL reference data and conducts an omnibus TWAS. We show that OTTERS is a practical and powerful TWAS tool by both simulations and application studies.

genetics↗

bioRxiv2022

Peptidoglycan recognition protein S2 is crucial for activation the Toll pathway against Israeli acute paralysis virus infection in honey bee Apis mellifera

Although honey bee responses to pathogens have been systematically described in the past decades, antiviral signalling pathways mechanisms are not thoroughly characterized. To decipher direct antiviral roles of an immune pathway, we firstly used the infectious clone of Israeli acute paralysis virus (IAPV) to screen 42 immune genes involved in mTOR, MAPK, Toll, Endocytosis, Jak-STAT pathway and homeobox protein, heat shock protein, as well as antimicrobial peptides (AMPs), and found that Toll pathway was a potential predominant immune pathway in Apis mellifera. Consistent with this, only dsRNA-PGRP-S2 treated A. mellifera significantly exhibited impaired activation of Toll pathway, promoting susceptibility to the IAPV infection. Finally, immunofluorescence results confirmed that the Toll pathway was initiated by peptidoglycan recognition protein S2 (PGRP-S2) interacting with Toll protein. Co-immunoprecipitation findings also further preliminarily confirmed PGRP-S2 directly interacting with viral capsid protein IAPV-VP3 to induce the activation of the Toll pathway in A. mellifera. These findings highlight that the Toll pathway is demanded efficient inhibitions of IAPV replication as a specific antiviral pathway in A. mellifera, and PGRP-S2, acting as a pattern recognition receptor, could be a new approach for control of the viral disease. Author summaryHoney bee viruses, particularly IAPV, had been implicated in the colony decline with a global distribution resulting in insufficient pollination services. However, little is known about the antiviral mechanism of honey bee. In this study, we found that the Toll pathway was required for A. mellifera against IAPV infection and initiated by PGRP-S2. We also confirmed that dsRNA-PGRP-S2 treated A. mellifera exhibited impaired Toll pathway activation and promoted susceptibility to the IAPV infection. As a result, we employed co-immunoprecipitation technique to identify the interaction between the PGRP-S2 with Toll. Moreover, it was found the PGRP-S2 directly recognized IAPV-VP3 to activate the immune pathway against IAPV infection. Our work provides novel evidence that honey bees own a specific antiviral immune pathway and suggests that targeting PGRP-S2 could be a new approach for controlling the viral disease.

immunology↗

bioRxiv2022

Mettl3-mediated m6A modification of Fgf16 restricts cardiomyocyte proliferation during heart regeneration

Cardiovascular disease is the leading cause of death worldwide due to the inability of adult heart to regenerate after injury. N6-methyladenosine (m6A) methylation catalyzed by the enzyme methyltransferase-like 3 (Mettl3) plays important roles in various physiological and pathological bioprocesses. However, the role of m6A in heart regeneration remains largely unclear. To study m6A function in heart regeneration, we modulated Mettl3 expression in vitro and in vivo. Knockdown of Mettl3 significantly increased the proliferation of cardiomyocytes and accelerated heart regeneration following heart injury in neonatal and adult mice. However, Mettl3 overexpression decreased cardiomyocyte proliferation and suppressed heart regeneration in postnatal mice. Conjoint analysis of methylated RNA immunoprecipitation sequencing (MeRIP-seq) and RNA-seq identified Fgf16 as a downstream target of Mettl3-mediated m6A modification during postnatal heart regeneration. RIP-qPCR and luciferase reporter assays revealed that Mettl3 negatively regulates Fgf16 mRNA expression in an m6A-Ythdf2-dependent manner. The silencing of Fgf16 suppressed the proliferation of cardiomyocytes. However, the overexpression of {Delta}Fgf16, in which the m6A consensus sequence was mutated, significantly increased cardiomyocyte proliferation and accelerated heart regeneration in postnatal mice compared with wild-type Fgf16. Our data demonstrate that Mettl3 post-transcriptionally reduces Fgf16 mRNA levels through an m6A-Ythdf2-dependen pathway, thereby controlling cardiomyocyte proliferation and heart regeneration.

cell biology↗