Effects of ethanol on the proteasome interacting proteins

Proteasome dysfunction has been repeatedly reported in alcoholic liver disease. Ethanol metabolism endproducts affect the structure of the proteasome, and, therefore, change the proteasome interaction with its regulatory complexes 19S and PA28, as well as its interacting proteins. Chronic ethanol feeding alters the ubiquitin-proteasome activity by altering the interaction between the 19S and the 20S proteasome interaction. The degradation of oxidized and damaged proteins is thus decreased and leads to accumulation of insoluble protein aggregates, such as Mallory-Denk bodies. Ethanol also affects the immunoproteasome formation. PA28a/b interactions with the 20S proteasome are decreased in the proteasome fraction isolated from the liver of rats fed ethanol chronically, thus affecting the cellular antigen presentation and defense against pathogenic agents. Recently, it has been shown that ethanol also affects the proteasome interacting proteins (PIPs). Interaction of the proteasome with Ecm29 and with deubiquitinating enzymes Rpn11, UCH37, and Usp14 has been found to decrease. However, the two UBL-ubiquitin-associated domain (UBA) PIPs p62 and valosin-containing protein are upregulated when the proteasome is inhibited. The increase of these UBL-UBA proteins, as well as the increase in Hsp70 and Hsp25 levels, compensated for the proteasome failure and helped in the unfolding/docking of misfolded proteins. Chronic alcohol feeding to rats causes a significant inhibition of the proteasome pathway and this inhibition results from a decreases of the interaction between the 20S proteasome and the regulatory complexes, PIPs, and the ubiquitin system components.

AAV mediated carboxyl terminus of Hsp70 interacting protein overexpression mitigates the cognitive and pathological phenotypes of APP/PS1 mice

The E3 ubiquitin ligase,carboxyl terminus of heat shock protein 70(Hsp70)interacting protein(CHIP),also functions as a co-chaperone and plays a crucial role in the protein quality control system.In this study,we aimed to investigate the neuroprotective effect of overexpressed CHIP on Alzheimer’s disease.We used an adeno-associated virus vector that can cross the blood-brain barrier to mediate CHIP overexpression in APP/PS1 mouse brain.CHIP overexpression significantly ameliorated the performance of APP/PS1 mice in the Morris water maze and nest building tests,reduced amyloid-βplaques,and decreased the expression of both amyloid-βand phosphorylated tau.CHIP also alleviated the concentration of microglia and astrocytes around plaques.In APP/PS1 mice of a younger age,CHIP overexpression promoted an increase in ADAM10 expression and inhibitedβ-site APP cleaving enzyme 1,insulin degrading enzyme,and neprilysin expression.Levels of HSP70 and HSP40,which have functional relevance to CHIP,were also increased.Single nuclei transcriptome sequencing in the hippocampus of CHIP overexpressed mice showed that the lysosomal pathway and oligodendrocyte-related biological processes were up-regulated,which may also reflect a potential mechanism for the neuroprotective effect of CHIP.Our research shows that CHIP effectively reduces the behavior and pathological manifestations of APP/PS1 mice.Indeed,overexpression of CHIP could be a beneficial approach for the treatment of Alzheimer’s disease.

Essential proteins identification method based on four-order distances and subcellular localization information

Essential proteins are inseparable in cell growth and survival. The study of essential proteins is important for understanding cellular functions and biological mechanisms. Therefore, various computable methods have been proposed to identify essential proteins. Unfortunately, most methods based on network topology only consider the interactions between a protein and its neighboring proteins, and not the interactions with its higher-order distance proteins. In this paper, we propose the DSEP algorithm in which we integrated network topology properties and subcellular localization information in protein–protein interaction(PPI) networks based on four-order distances, and then used random walks to identify the essential proteins. We also propose a method to calculate the finite-order distance of the network, which can greatly reduce the time complexity of our algorithm. We conducted a comprehensive comparison of the DSEP algorithm with 11 existing classical algorithms to identify essential proteins with multiple evaluation methods. The results show that DSEP is superior to these 11 methods.

Screening for Novel Binding Proteins Interacting with Human Papillomavirus Type 18 E6 Oncogene in the Hela cDNA Library by Yeast Two-Hybrid System

To screen for novel binding proteins interacting with high-risk HPV 18 E6 oncogene, the strain AH 109 was transformed with pGBKT7-HPV 18 E6 plasmid, and subsequent transference was utilized to screen for interacting proteins with HPV 18 E6 in human Hela cDNA library. HPV 18 E6 mRNA was expressed in yeast and there was no self-activation and toxicity in AH109. Seven proteins that interacted with HPV18 E6, including transmembrane protein 87B, phosphonoformate immuno-associated protein 5, vimentin, KM-HN-1 protein, dedicator of cytokinesis 7, vaccinia related kinase 2 and a hypothetical protein, were identified. It was suggested that yeast two-hybrid system is an efficient for screening interacting proteins. The high-risk HPV 18 E6 oncogene may interact with the proteins, which may be associated with signal transduction and transcriptional control, epithelial cell invasion and migration, as well as humoral and cellular immune etc. This investigation provides functional clues for further exploration of potential oncogenesis targets for cancer biotherapy.

Screening of Proteins Interacting with Nonstructural 1 Protein of H5N1 Avian Influenza Virus from T7-phage Display Library

Avian influenza virus（AIV） nonstructural 1（NS1） gene was amplified by real-time polymerse chain reac tion（RT-PCR） and inserted into pET28a, then transformed into E. coli BL21（DE3） competent cell. With the induction of isopropyl-β-D-thiogalactoside（IPTG） and the purification of Ni-NTA column, we finally obtained purified NS1 protein. T7-phage display system was used to screen the proteins that interacted with NS1 from lung cell cDNA li brary. The selected positive clones were identified by DNA sequencing and analyzed by BLAST program in Gene Bank. Two proteins were obtained as NS1 binding proteins, Homo sapiens nucleolar and coiled-body phosphoprotein 1（NOLC1） and Homo sapiens similar to colon cancer-associated antigen. By co-immunoprecipitation and other me thods, Homo sapiens NOLC1 was found to interact with the NS1 protein, the results would provide the basis for fur ther studying biological function of NS1 protein.

Isolation and Characterization of Proteins Interacting with Activin Type Ⅱ Receptors

Regulation of the number of aetivin receptors that are present in the cell membrane plays a key role in the modulation of cellular responses to activin. In order to find the regulators, a novel protein ARIPzip, interacting with activin type II receptors, was searched and identified by using yeast two-hybrid screening. ARIPzip is a splicing variant of ARIP2. This has been discussed previously. ARIPzip can specifically interact with ActR Ⅱ A, and is widely distributed in mouse tissues. Overexpression of ARIPzip can cause the activin-induced transcriptional activities to increase in a dose-dependent manner while the overexpression of ARIV2 can decrease these activities. These data suggest that the C-terminal rezions of ARIP2 and ARIPzip are involved in the regulation of activin signaling.

Identification,evolution,expression and protein interaction analysis of genes encoding B-box zinc-finger proteins in maize

The B-box(BBX)family of proteins consists of zinc-finger transcription factors with one or two highly conserved B-box motifs at their N-termini.BBX proteins play crucial roles in various aspects of plant growth and development,including seedling photomorphogenesis,shade avoidance,flowering time,and biotic and abiotic stress responses.Previous studies have identified many different BBXs from several plant species,although the BBX family members in maize are largely unknown.Genome-wide identification and comprehensive analysis of maize BBX(ZmBBX)expression and interaction networks would therefore provide valuable information for understanding their functions.In this study,36 maize BBXs in three major clades were identified.The ZmBBXs within a given clade were found to share similar domains,motifs,and genomic structures.Gene duplication analyses revealed that the expansion of BBX proteins in maize has mainly occurred by segmental duplication.The expression levels of ZmBBXs were analyzed in various organs and tissues,and under different abiotic stress conditions.Protein–protein interaction networks of ZmBBXs were established using bioinformatic tools and verified by bimolecular fluorescence complementation(BiFC)assays.Our findings can facilitate a greater understanding of the complexity of the ZmBBX family and provide novel clues for unravelling ZmBBX protein functions.

Screening of Host Proteins Interacting with PorcineEpidemic Diarrhea Virus (PEDV) N Protein by YeastTwo-hybrid System

[Objective] The paper was to obtain host proteins interacting with porcine epidemic diarrhea virus （PEDV） N protein. [Method] The re-combinant vector pGBKT7-N of PEDV N gene was constructed and used as the bait plasmid to screen the proteins interacting with N protein ofPEDV from the cDNA library of porcine alveolar macrophage （PAM） by yeast two-hybrid method. [Result] There was no toxicity and self activationof bait protein in yeast hybridization system, and six proteins （FTH1, LGALS3, CORO1C, SNRPG, KRTAP5-3, ZNF598） interacting with N proteinwere indentified. It was confirmed that LGALS3 and SNRPG had specific interaction with N protein by return experiment and co-immunoprecipitation（CoIP） test. [Conclusion] The study lays a foundation for further studying the function of PEDV N protein and the pathogenic mechanism of PEDV.

Calcium/calmodulin modulates salt responses by binding a novel interacting protein SAMS1 in peanut(Arachis hypogaea L.)

The Ca^(2+)/CaM signal transduction pathway helps plants adapt to environmental stress. However, our knowledge on the functional proteins of C^(2+)/CaM pathway in peanut(Arachis hypogeae L.) remains limited. In the present study, a novel calmodulin 4(CaM4)-binding protein S-adenosyl-methionine synthetase 1(SAMS1) in peanut was identified using a yeast two-hybrid assay. Expression of AhSAMS1was induced by Ca^(2+), ABA, and salt stress. To elucidate the function of AhSAMS1, physiological and phenotypic analyses were performed with wild-type and transgenic materials. Overexpression of AhSAMS1increased spermidine and spermidine synthesis while decreased the contents of ethylene, thereby eliminating excessive reactive oxygen species(ROS) in transgenic lines under salt stress. AhSAMS1 reduced uptake of Na+and leakage of K+from mesophyll cells, and was less sensitive to salt stress during early seedling growth, in agreement with the induction of SOS and NHX genes Transcriptomics combined with epigenetic regulation uncovered relationships between differentially expressed genes and differentially methylated regions, which raised the salt tolerance and plants growth. Our findings support a model in which the role of AhSAMS1 in the ROS-dependent regulation of ion homeostasis was enhanced by Ca^(2+)/CaM while AhSAMS1-induced methylation was regulated by CaM, thus providing a new strategy for increasing the tolerance of plants to salt stress.

GST family genes in jujube actively respond to phytoplasma infection

Jujube witches’broom(JWB)caused by phytoplasma has a severely negative effect on multiple metabolisms in jujube.The GST gene family in plants participates in the regulation of a variety of biotic and abiotic stresses.This study aims to identify and reveal the changes in the jujube GST gene family in response to phytoplasma infection.Here,70 ZjGSTs were identified in the jujube genome and divided into 8 classes.Among them,the Tau-class,including 44 genes,was the largest.Phylogenetic analysis indicated that Tau-class genes were highly conserved among species,such as Arabidopsis,cotton,chickpea,and rice.Through chromosome location analysis,37.1%of genes were clustered,and 8 of 9 gene clusters were composed of Tau class members.Through RT-PCR,qRT-PCR and enzyme activity detection,the results showed that the expression of half(20/40)of the tested ZjGSTs was inhibited by phytoplasma infection in field and tissue culture conditions,and GST activity was also significantly reduced.In the resistant and susceptible varieties under phytoplasma infection,ZjGSTU49-ZjGSTU54 in the cluster IV showed opposite expression patterns,which may be due to functional divergence during evolution.Some upregulated genes(ZjGSTU45,ZjGSTU49,ZjGSTU59,and ZjGSTU70)might be involved in the process of jujube against JWB.The yeast two-hybrid results showed that all 6 Tauclass proteins tested could form homodimers or heterodimers.Overall,the comprehensive analysis of the jujube GST gene family revealed that ZjGSTs responded actively to phytoplasma infection.Furthermore,some screened genes(ZjGSTU24,ZjGSTU49-52,ZjGSTU70,and ZjDHAR10)will contribute to further functional studies of jujube-phytoplasma interactions.

Wheat kinase TaSnRK2.4 forms a functional module with phosphatase TaPP2C01 and transcription factor TaABF2 to regulate drought response

SNF1-related protein kinase 2(SnRK2)family members are essential components of the plant abscisic acid(ABA)signaling pathway initiated by osmotic stress and triggering a drought stress response.This study characterized the molecular properties of TaSnRK2.4 and its function in mediating adaptation to drought in Triticum aestivum.Transcripts of TaSnRK2.4 were upregulated upon drought and ABA signaling and associated with drought-and ABA-responsive cis-elements ABRE and DRE,and MYB and MYC binding sites in the promoter as indicated by reporter GUS protein staining and activity driven by truncations of the promoter.Yeast two-hybrid,BiFC,and Co-IP assays indicated that TaSnRK2.4 protein interacts with TaPP2C01 and an ABF transcription factor(TF)TaABF2.The results suggested that TaSnRK2.4 forms a functional TaPP2C01-TaSnRK2.4-TaABF2 module with its upstream and downstream partners.Transgene analysis revealed that TaSnRK2.4 and TaABF2 positively regulate drought tolerance whereas TaPP2C01 acts negatively by modulating stomatal movement,osmotic adjustment,reactive oxygen species(ROS)homeostasis,and root morphology.Expression analysis,yeast one-hybrid,and transcriptional activation assays indicated that several osmotic stress-responsive genes,including TaSLAC1-4,TaP5CS3,TaSOD5,TaCAT1,and TaPIN4,are regulated by TaABF2.Transgene analysis verified their functions in positively regulating stomatal movement(TaSLAC1-4),proline accumulation(TaP5CS3),SOD activity(TaSOD5),CAT activity(TaCAT1),and root morphology(TaPIN4).There were high correlations between plant biomass and yield with module transcripts in a wheat variety panel cultivated under drought conditions in the field.Our findings provide insights into understanding plant drought response underlying the SnRK2 signaling pathway in common wheat.

Upregulated lncRNA PRNT promotes progression and oxaliplatin resistance of colorectal cancer cells by regulating HIPK2 transcription

BACKGROUND Colorectal cancer(CRC)is the third most common cancer and a significant cause of cancer-related mortality globally.Resistance to chemotherapy,especially during CRC treatment,leads to reduced effectiveness of drugs and poor patient outcomes.Long noncoding RNAs(lncRNAs)have been implicated in various pathophysiological processes of tumor cells,including chemotherapy resistance,yet the roles of many lncRNAs in CRC remain unclear.AIM To identify and analyze the lncRNAs involved in oxaliplatin resistance in CRC and to understand the underlying molecular mechanisms influencing this resistance.METHODS Gene Expression Omnibus datasets GSE42387 and GSE30011 were reanalyzed to identify lncRNAs and mRNAs associated with oxaliplatin resistance.Various bioinformatics tools were employed to elucidate molecular mechanisms.The expression levels of lncRNAs and mRNAs were assessed via quantitative reverse transcription-polymerase chain reaction.Functional assays,including MTT,wound healing,and Transwell,were conducted to investigate the functional implications of lncRNA alterations.Interactions between lncRNAs and trans-cription factors were examined using RIP and luciferase reporter assays,while Western blotting was used to confirm downstream pathways.Additionally,a xenograft mouse model was utilized to study the in vivo effects of lncRNAs on chemotherapy resistance.RESULTS LncRNA prion protein testis specific(PRNT)was found to be upregulated in oxaliplatin-resistant CRC cell lines and negatively correlated with homeodomain interacting protein kinase 2(HIPK2)expression.PRNT was demonstrated to sponge transcription factor zinc finger protein 184(ZNF184),which in turn could regulate HIPK2 expression.Altered expression of PRNT influenced CRC cell sensitivity to oxaliplatin,with overexpression leading to decreased sensitivity and decreased expression reducing resistance.Both RIP and luciferase reporter assays indicated that ZNF184 and HIPK2 are targets of PRNT.The PRNT/ZNF184/HIPK2 axis was implicated in promoting CRC progression and oxaliplatin resistance both in vitro and in vivo.CONCLUSION The study concludes that PRNT is upregulated in oxaliplatin-resistant CRC cells and modulates the expression of HIPK2 by sponging ZNF184.This regulatory mechanism enhances CRC progression and resistance to oxaliplatin,positioning PRNT as a promising therapeutic target for CRC patients undergoing oxaliplatin-based chemotherapy.

Assessment of pathogenicity and functional characterization of APPL1 gene mutations in diabetic patients

BACKGROUND Adaptor protein,phosphotyrosine interacting with PH domain and leucine zipper 1(APPL1)plays a crucial role in regulating insulin signaling and glucose metabolism.Mutations in the APPL1 gene have been associated with the development of maturity-onset diabetes of the young type 14(MODY14).Currently,only two mutations[c.1655T>A(p.Leu552*)and c.281G>A p.(Asp94Asn)]have been identified in association with this disease.Given the limited understanding of MODY14,it is imperative to identify additional cases and carry out comprehensive research on MODY14 and APPL1 mutations.AIM To assess the pathogenicity of APPL1 gene mutations in diabetic patients and to characterize the functional role of the APPL1 domain.METHODS Patients exhibiting clinical signs and a medical history suggestive of MODY were screened for the study.Whole exome sequencing was performed on the patients as well as their family members.The pathogenicity of the identified APPL1 variants was predicted on the basis of bioinformatics analysis.In addition,the pathogenicity of the novel APPL1 variant was preliminarily evaluated through in vitro functional experiments.Finally,the impact of these variants on APPL1 protein expression and the insulin pathway were assessed,and the potential mechanism underlying the interaction between the APPL1 protein and the insulin receptor was further explored.RESULTS A total of five novel mutations were identified,including four missense mutations(Asp632Tyr,Arg633His,Arg532Gln,and Ile642Met)and one intronic mutation(1153-16A>T).Pathogenicity prediction analysis revealed that the Arg532Gln was pathogenic across all predictions.The Asp632Tyr and Arg633His variants also had pathogenicity based on MutationTaster.In addition,multiple alignment of amino acid sequences showed that the Arg532Gln,Asp632Tyr,and Arg633His variants were conserved across different species.Moreover,in in vitro functional experiments,both the c.1894G>T(at Asp632Tyr)and c.1595G>A(at Arg532Gln)mutations were found to downregulate the expression of APPL1 on both protein and mRNA levels,indicating their pathogenic nature.Therefore,based on the patient’s clinical and family history,combined with the results from bioinformatics analysis and functional experiment,the c.1894G>T(at Asp632Tyr)and c.1595G>A(at Arg532Gln)mutations were classified as pathogenic mutations.Importantly,all these mutations were located within the phosphotyrosinebinding domain of APPL1,which plays a critical role in the insulin sensitization effect.CONCLUSION This study provided new insights into the pathogenicity of APPL1 gene mutations in diabetes and revealed a potential target for the diagnosis and treatment of the disease.

Thioredoxin interacting protein,a key molecular switch between oxidative stress and sterile inflammation in cellular response

Tissue and systemic inflammation have been the main culprit behind the cellular response to multiple insults and maintaining homeostasis.Obesity is an independent disease state that has been reported as a common risk factor for multiple metabolic and microvascular diseases including nonalcoholic fatty liver disease(NAFLD),retinopathy,critical limb ischemia,and impaired angiogenesis.Sterile inflammation driven by high-fat diet,increased formation of reactive oxygen species,alteration of intracellular calcium level and associated release of inflammatory mediators,are the main common underlying forces in the pathophysiology of NAFLD,ischemic retinopathy,stroke,and aging brain.This work aims to examine the contribution of the pro-oxidative and pro-inflammatory thioredoxin interacting protein(TXNIP)to the expression and activation of NLRP3-inflammasome resulting in initiation or exacerbation of sterile inflammation in these disease states.Finally,the potential for TXNIP as a therapeutic target and whether TXNIP expression can be modulated using natural antioxidants or repurposing other drugs will be discussed.

Interaction among Rb/p16, Rb/E2F1 and HDAC1 Proteins in Gallbladder Carcinoma

The mechanism and interaction among Rb/p16, Rb/E2F1 and HDAC1 proteins in gallbladder carcinoma were investigated. By using the immunoprecipitation method, the interactions among Rb, p16, E2F1, HDAC1 proteins in gallbladder carcinoma cell line （Mz-ChA-1） were studied. It was found that there were Rb and E2F1 proteins in the precipitates with anti-HDAC1, and there were HDAC1 and E2F1 proteins in the precipitate with anti-Rb. It was concluded that there are specific interactions among Rb, HDAC1 and E2F1 proteins in gallbladder carcinoma, indicating the existence of the direct Rb/E2F1/HDAC1 signal transduction pathway. There is no direct relationship between p16 proteins with Rb, HDAC1, and E2F1 proteins.

Complex interactomes and post-translational modifications of the regulatory proteins HABP4 and SERBP1 suggest pleiotropic cellular functions

The 57 kDa antigen recognized by the Ki-1 antibody,is also known as intracellular hyaluronic acid binding protein 4 and shares 40.7%identity and 67.4%similarity with serpin mRNA binding protein 1,which is also named CGI-55,or plasminogen activator inhibitor type-1-RNA binding protein-1,indicating that they might be paralog proteins,possibly with similar or redundant functions in human cells.Through the identification of their protein interactomes,both regulatory proteins have been functionally implicated in transcriptional regulation,mRNA metabolism,specifically RNA splicing,the regulation of mRNA stability,especially,in the context of the progesterone hormone response,and the DNA damage response.Both proteins also show a complex pattern of post-translational modifications,involving Ser/Thr phosphorylation,mainly through protein kinase C,arginine methylation and SUMOylation,suggesting that their functions and locations are highly regulated.Furthermore,they show a highly dynamic cellular localization pattern with localizations in both the cytoplasm and nucleus as well as punctuated localizations in both granular cytoplasmic protein bodies,upon stress,and nuclear splicing speckles.Several reports in the literature show altered expressions of both regulatory proteins in a series of cancers as well as mutations in their genes that may contribute to tumorigenesis.This review highlights important aspects of the structure,interactome,post-translational modifications,sub-cellular localization and function of both regulatory proteins and further discusses their possible functions and their potential as tumor markers in different cancer settings.

Screening of Rice Genes Interacting with p5b of Rice BlackStreaked Dwarf Virus

Rice black-streaked dwarf virus （RBSDV） is a recognized member of the genus Fijivirus, family Reoviridae. Its genome has ten double-stranded RNA （dsRNA） segments （$1-$10）, in which the fifth genome segment （$5） contains two open reading frames （ORFs） with a partially overlapping region. The second ORF of RBSDV S5 encodes a viral nonstructural protein named p5b with unknown function. To reveal the function of p5b, its gene was ligated into the bait plasmid pGBKT7 and an expression library containing rice cDNAs was constructed using plasmid pGADT7 for yeast two-hybrid assay. The bait protein p5b was detected in yeast by western blot, and the result of an auto-activation test showed that p5b could not autonomously activate the expression of reporter genes in yeast. Then the bait protein p5b was used for screening the cDNA expression libraries of rice. Gene fragments of some pivotal enzymes involved in photosynthesis, respiration and other important metabolic processes, were identified to interact with p5b in yeast, suggesting that these interactions may play roles in symptom development in infected plants.

Protein-mediated interactions in the dynamic regulation of acute inflammation

Protein-mediated interactions are the fundamental mechanism through which cells regulate health and disease.These interactions require physical contact between proteins and their respective targets of interest.These targets include not only other proteins but also nucleic acids and other important molecules as well.These proteins are often involved in multibody complexes that work dynamically to regulate cellular health and function.Various techniques have been adapted to study these important interactions,such as affinity-based assays,mass spectrometry,and fluorescent detection.The application of these techniques has led to a greater understanding of how protein interactions are responsible for both the instigation and resolution of acute inflammatory diseases.These pursuits aim to provide opportunities to target specific protein interactions to alleviate acute inflammation.

Protocadherin gamma C3:a new player in regulating vascular barrier function

Defects in the endothelial cell barrier accompany diverse malfunctions of the central nervous system such as neurodegenerative diseases,stroke,traumatic brain injury,and systemic diseases such as sepsis,viral and bacterial infections,and cancer.Compromised endothelial sealing leads to leaking blood vessels,followed by vasogenic edema.Brain edema as the most common complication caused by stroke and traumatic brain injury is the leading cause of death.Brain microvascular endothelial cells,together with astrocytes,pericytes,microglia,and neurons form a selective barrier,the so-called blood-brain barrier,which regulates the movement of molecules inside and outside of the brain.Mechanisms that regulate blood-brain barrier permeability in health and disease are complex and not fully understood.Several newly discovered molecules that are involved in the regulation of cellular processes in brain microvascular endothelial cells have been described in the literature in recent years.One of these molecules that are highly expressed in brain microvascular endothelial cells is protocadherin gamma C3.In this review,we discuss recent evidence that protocadherin gamma C3 is a newly identified key player involved in the regulation of vascular barrier function.

Serine protease inhibitors LmSPN2 and LmSPN3 co-regulate embryonic diapause in Locusta migratoria manilensis(Meyen)via the Toll pathway

Female adults of the migratory locust,Locusta migratoria manilensis(Meyen),can sense seasonal photoperiod changes,which induces embryonic diapause as a key strategy to overwinter.Serine protease inhibitor genes(SPNs)were thought to play key roles during diapause,while few SPNs were functionally characterized.LmSPN2 was one of those genes differentially expressed between diapause and non-diapause eggs;however,its biological function remained to be explored.So,we conducted RNAi knockdown of LmSPN2,resulting in a significant decrease of the egg diapause rate by 29.7%.Using yeast two-hybrid assays,co-immunoprecipitation,and pull-down methods,we found an interaction between LmSPN2 and LmSPN3,which was proved to be mediated by a glutamate(E331)binding site of LmSPN2.RNAi knockdown of LmSPN3 resulted in a significant increase in diapause rate by 14.6%,indicating an inverse function of LmSPN2 and LmSPN3 on diapause regulation.Double knockdown of two SPN genes resulted in a 26.4%reduction in diapause rate,indicating that LmSPN2 was the dominant regulatory signal.Moreover,we found four Toll pathway genes(easter,spätzle,pelle,and dorsal)upregulated significantly after the knockdown of LmSPN2 while downregulated after the knockdown of LmSPN3.Therefore,we speculate that two SPNs regulate diapause through the Toll pathway.Our results indicated that LmSPN2 positively regulates locust egg entry into diapause,while LmSPN3 is a negative regulator of embryonic commitment to diapause.Their interaction is mediated by the binding site of E331 and influences egg diapause through the Toll pathway.This mechanistic understanding of diapause regulation expands our understanding of insect developmental regulation and provides functional targets for developing locust management strategies.