Biology subjects

Du, T.

Publications and source records attributed to Du, T..

17 recordsLinked to original sources

bioRxiv2026

RNA m6A demethylase ALKBH4 governs whitefly development

N6-methyladenosine (m6A) modification is the most predominant and ubiquitous internal modification of RNA in eukaryotes, serving as a key post-transcriptional regulator of gene expression that is dynamically modulated by methyltransferases (writers) and demethylases (erasers). However, while the functions of m6A methylases have been partially elucidated in insects, the identity of m6A erasers in arthropods and their chemical catalytic mechanisms, as well as biological functions, remains largely enigmatic. Here, we uncovered 2499 putative methylase genes and 1148 putative demethylase genes in 266 insect genomes, and demonstrated that ALKBH4 functions as an m6A demethylase in the whitefly, Bemisia tabaci, catalyzing the oxidative reversal of mRNA m6A modifications both in vitro and in vivo. Furthermore, we established that ALKBH4, in coordination with other core components of the m6A pathway, fulfills an essential function in regulating the transcript stability of Imaginal Disk Growth Factor 1 (IDGF1) during whitefly development. Collectively, our findings expand the evolutionary scope of the eukaryotic m6A modification system, and reveal a conserved yet insect-specific epitranscriptomic regulatory mechanism governing fundamental physiological processes and adaptive phenotypes. Significance statementThe addition of a methyl group to the N6-position of adenosine (m6A) is a highly abundant chemical modification of RNA. However, the functional role of m6A in insects and the key enzymes that regulate its levels remains poorly understood. In this study, we explored putative methylase genes and demethylase genes in hundreds insect genomes, and identified an m6A RNA demethylase, ALKBH4, in the whitefly, Bemisia tabaci. We demonstrate that ALKBH4 oxidatively reverses mRNA methylation in vivo and in vitro, in combination with other components of the m6A pathway, plays an important role in whitefly development. These findings provide new insight into m6A methylation system of insect.

zoology↗

bioRxiv2026

Intranasal oxytocin mRNA-LNP can promote social behaviour and reduce pain

The COVID-19 epidemic and success of mRNA-LNP vaccines demonstrated the transformative potential of mRNA therapeutics. Beyond vaccination, mRNA delivery offers a platform for transient on-demand expression of therapeutic proteins for both rare and common diseases. While delivery of therapeutics to the liver is relatively straightforward, targeted delivery of mRNA-LNPs to the central nervous system (CNS) remains a significant challenge. Here we show that intranasal mRNA-LNP delivery results in localized mRNA cargo uptake and functional expression in the respiratory and olfactory epithelium, where the encoded cargo protein is secreted and can enter the CNS. Guided by genomic data of pain-associated gene expression, we identified secreted proteins as candidate mRNA-encoded analgesics. Intranasal mRNA-LNP encoding a synthetic oxytocin transcript (OXT) resulted in bioactive oxytocin peptide delivery to the CNS. Functionally, intranasal OXT mRNA-LNP enhanced social behaviour and attenuated pain responses across multiple behavioural paradigms, without impairing motor coordination. Importantly, repeated dosing was well tolerated and intranasal mRNA-LNP did not elicit an inflammatory response or alter overall health. Together, these findings establish intranasal mRNA-LNP delivery of secreted ligands as a safe, non-invasive route to target the CNS, unlocking a new class of mRNA therapeutics for pain or other disorders of the brain. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=189 SRC="FIGDIR/small/711938v1_ufig1.gif" ALT="Figure 1"> View larger version (39K): org.highwire.dtl.DTLVardef@131252aorg.highwire.dtl.DTLVardef@17efb79org.highwire.dtl.DTLVardef@1afe479org.highwire.dtl.DTLVardef@c0f2f5_HPS_FORMAT_FIGEXP M_FIG C_FIG One sentence summaryIntranasal administration of mRNA-LNP enables local transfection in nasal epithelium and subsequent secretion of therapeutic oxytocin peptides into the brain, promoting social interactions and reducing pain.

neuroscience↗

bioRxiv2025

Mechanical Ventilation Suppresses Glymphatic Function in Parallel with Delirium-Like Symptoms in Mice

Delirium is a common and serious complication in critically ill patients, arising from multiple overlapping risk factors. Its pathogenesis remains poorly understood because it reflects the combined effects of interacting clinical insults, and because appropriate experimental models for mechanistic studies have been lacking. Delirium most commonly develops in patients undergoing major surgery or requiring intensive care, where inhalational anesthesia, opioid sedation, and mechanical ventilation are common clinical exposures. Here, we tested the hypothesis that these clinically relevant interventions are sufficient to induce delirium-like behavior in healthy young wild-type mice by disrupting cerebrospinal fluid (CSF) glymphatic transport. The analysis showed that inhalational anesthesia combined with mechanical ventilation increased intracranial pressure (ICP) and induced a sustained suppression and rerouting of glymphatic waste clearance, resulting in impaired waste clearance, and acute cytokine accumulation. These findings identify disruption of brain fluid dynamics as a potential mechanism contributing to delirium in perioperative and intensive care settings. Equally important, this model represents a distinct experimental platform that combines clinically relevant mechanical ventilation, inhalational anesthesia, and opioid analgesia to produce delirium-like behavioral abnormalities in otherwise healthy mice. It therefore provides a powerful tool for future mechanistic studies of delirium pathogenesis.

neuroscience↗

bioRxiv2025

Structural insights into Measles virus RNA synthesis: C protein-mediated regulation of replication-transcription switch and allosteric inhibition by ERDRP-0519

Nonsegmented negative-sense RNA viruses (nsNSVs) rely on a multifunctional RNA-dependent RNA polymerase (RdRP) complex for transcription and replication. In measles virus (MeV), the nonstructural protein C has long been implicated in regulating RNA synthesis, yet its precise role remains unclear. Here, we show that the MeV C protein directly associates with the RdRP complex. Using cryo-electron microscopy, we determined atomic-resolution structures of the MeV polymerase with and without C, revealing that C binding stabilizes the accessory domains of L and locks the complex into a replication-competent elongation state. Biochemical data further show that C promotes N protein recruitment, enhancing polymerase processivity through facilitating encapsidation during replication. Additionally, we also resolved high-resolution structures of MeV and Nipah virus (NiV) polymerases bound to ERDRP-0519, an orally available morbillivirus inhibitor. Unexpectedly, the compound occupies a previously unrecognized allosteric pocket within the RdRp domain, rather than the predicted PRNTase domain, overlapping conserved resistance sites. This binding induces conformational changes in palm subdomain, blocking RNA template and nucleotide engagement, thereby halting RNA synthesis. These findings uncover distinct regulatory and inhibitory mechanisms in paramyxovirus polymerases and provide a structural framework for the rational design of broad-spectrum antivirals targeting MeV, NiV, and potentially other clinically relevant nsNSVs.

microbiology↗

bioRxiv2024

Inferring in vivo murine cerebrospinal fluid flow using artificial intelligence velocimetry with moving boundaries and uncertainty quantification

Cerebrospinal fluid (CSF) flow is crucial for clearing metabolic waste from the brain, a process whose dysregulation is linked to neurodegenerative diseases like Alzheimers. Traditional approaches like particle tracking velocimetry (PTV) are limited by their reliance on single-plane two-dimensional measurements, which fail to capture the complex dynamics of CSF flow fully. To overcome these limitations, we employ Artificial Intelligence Velocimetry (AIV) to reconstruct three-dimensional velocities, infer pressure and wall shear stress, and quantify flow rates. Given the experimental nature of the data and inherent variability in biological systems, robust uncertainty quantification (UQ) is essential. Towards this end, we have modified the baseline AIV architecture to address aleatoric uncertainty caused by noisy experimental data, enhancing our measurement refinement capabilities. We also implement UQ for the model and epistemic uncertainties arising from the governing equations and network representation. Toward this end, we test multiple governing laws, representation models, and initializations. Our approach not only advances the accuracy of CSF flow quantification but also can be adapted to other applications that use physics-informed machine learning to reconstruct fields from experimental data, providing a versatile tool for inverse problems.

neuroscience↗

bioRxiv2024

Luminescent ingestible electronic capsules for in vivo regulation of optogenetic engineered bacteria

AbstractsThe ideal engineered microbial smart-drug should be capable of functioning on demand at specific sites in vivo. However, precise regulation of engineered microorganisms poses challenges in the convoluted and elongated intestines. Despite the promising application potential of optogenetic regulation strategies based on light signals, the poor tissue penetration of light signals limits their application in large experimental animals. Given the rapid development of ingestible electronic capsules in recent years, taking advantage of them as regulatory devices to deliver light signals in situ to engineered bacteria within the intestines has become feasible. In this study, we established an electronic-microorganism signaling system, realized by two Bluetooth-controlled luminescent electronic capsules were designed. The "Manager" capsule is equipped with a photosensor to monitor the distribution of engineered bacteria and to activate the optogenetic function of the bacteria by emitting green light. The other capsule, "Locator", can control the in situ photopolymerization of hydrogels in the intestines via ultraviolet light, aiding in the retention of engineered bacteria at specific sites. These two electronic capsules are expected to work synergistically to regulate the distribution and function of engineered bacteria in vivo, and their application in the treatment of colitis in pigs is currently being investigated, with relevant results to be updated subsequently.

synthetic biology↗

bioRxiv2024

Establishing remote communication between human operator and engineered intestinal microbe via bio-electronic optical language

Synthetic biology enables microbes to be engineered to detect biomarkers and deliver therapies in situ, offering advantages such as self-replication and localized response and treatment. However, the engineered microbes in the intestine remains a "black box", the status of microbial functionality is inaccessible, and the activation of microbial functions is uncontrollable. There is a demand of a "language" between microbes and human for real-time and in-situ monitoring and controlling engineered microbes in the intestine. Light, due to its advantages of specificity and accuracy in the body, was chosen as the language to establish an interactive communication path between human and the microbes with the features of sophisticated monitoring and controlling. For effectively remote operation of this "language" in the intestine, we introduced an electronic capsule as the intermedia, translating information and instructions understandable for human operator into bacterial regulatory and detectable signals in vivo. In this paper, the electronic capsule and the engineered Escherichia coli Nissle 1917 (EcN) strains were designed in a collaborative manner. An EcN-to-capsule bioluminescent signal transmission was established and testified as the language to report the status of engineered EcN, especially the response of EcN to intestinal environment. Similarly, another capsule-to-EcN optogenetic signal transmission was established and testified as the language to control the function of engineered EcN, especially the secretion of therapeutic substances. On this basis, bidirectional communication between human operator and intestinal microbes was achieved via bidirectional bio-electronic optical language. The communication was established to monitor and regulate engineered EcN community in the intestine in 50-90 kg live pigs. The in vitro and in vivo estimations demonstrated the capabilities of monitoring and regulating the engineered microbes, offering a remotely controllable language-based communication between human operator and internal intestinal microbes.

synthetic biology↗

bioRxiv2022

Loss of aquaporin-4 results in glymphatic system dysfunction via brain-wide interstitial fluid stagnation

The glymphatic system is a fluid transport network of cerebrospinal fluid (CSF) entering the brain along arterial perivascular spaces, exchanging with interstitial fluid (ISF), ultimately establishing directional clearance of interstitial solutes. CSF transport is facilitated by the expression of aquaporin-4 (AQP4) water channels on the perivascular endfeet of astrocytes. Mice with genetic deletion of AQP4 (AQP4 KO) exhibit abnormalities in the brain structure and molecular water transport. Yet, no studies have systematically examined how these abnormalities in structure and water transport correlate with glymphatic function. Here we used high-resolution 3D magnetic resonance (MR) non-contrast cisternography, diffusion-weighted MR imaging (MR-DWI) along with intravoxel-incoherent motion (IVIM) DWI, while evaluating glymphatic function using a standard dynamic contrast-enhanced MR imaging to better understand how water transport and glymphatic function is disrupted after genetic deletion of AQP4. AQP4 KO mice had larger interstitial spaces and total brain volumes resulting in higher water content and reduced CSF space volumes, despite similar CSF production rates and vascular density compared to wildtype mice. The larger interstitial fluid volume likely resulted in increased slow but not fast MR diffusion scores and coincided with reduced glymphatic influx. This markedly altered brain fluid transport in AQP4 KO mice may result from a reduction in glymphatic clearance, leading to stagnation of ISF movement and enlargement of the interstitial space. Overall, diffusion MR is a useful tool to evaluate glymphatic function and may serve as valuable translational biomarker to study glymphatics in human disease.

neuroscience↗

bioRxiv2022

Comprehensive dissection of immune microenvironment in the progression of early gastric cancer at spatial and single-cell resolution

While the changes of tumor immune microenvironment (TME) have critical implications for most tumor progression, works that could reveal the compositions and immunity features of TME are needed. Profiling gastric malignant cells at single-cells resolution has shown the transcriptional heterogeneity is represented at different states of gastric cancer, implying that diverse cell states may exist, including immune cells, and all components in TME make some balances in early gastric cancer (EGC) progression. However, it remains unclear how immune cells contributing malignancy of gastritis, constituting general characteristics of gastric TME. Furthermore, the role of specific interactions among cells in gastric TME remains to be illustrated. Here, we performed spatial transcriptomes and single-cell RNA-seq analysis across 18 gastric samples, identifying 17 celltypes and reconstructing their location information. We found that immune cells represented different degree of dysregulations during the progression from non-atrophic gastritis (NAG), atrophic gastritis (AG) to EGC, including imbalance of cytotoxic and inhibitory effects in T cells, maturation inhibition in B cells and malignant genes up-regulated obviously in myeloid cells. Besides, pathway activities showed that hypoxia, reactive oxygen species and fatty metabolism signaling were activated from AG stage, which may accelerate progression of EGC. Moreover, cellular interactions further identified the roles of hypoxia in gastric TME. Overall, the multi-omics data presented in this study offer a comprehensive view of immune cell types, states changes and locations within the gastric tissues during the progression from NAG, AG to EGC, advancing our understanding of the composition and immunity of different gastric states, offering diagnostic and preventive thoughts for EGC.

cancer biology↗

bioRxiv2021

Ca2+ activity is required for injury-induced migration of microglia

ObjectivesMicroglia are the resident immune cells in the brain. Brain injury can activate the microglia and induce its directional migration towards injury sites for exerting immune functions. While extracellular ATP released from the injury site mediates the directionality of activated microglias migration, what endows activated microglia with migration capability remains largely unexplored. MethodsIn the present study, we used the larval zebrafish as an in vivo model to visualize the dynamics of both morphology and Ca2+ activity of microglia during its migration evoked by local brain injury. ResultsWe found that, in response to local injury, activated microglia exhibited an immediate Ca2+ transient and later elevated Ca2+ bursts frequency during its migration towards the local injury site (P < 0.01). Furthermore, suppression of Ca2+ activities significantly retarded microglial migration (P < 0.05). ConclusionThus, our study suggests that intracellular Ca2+ activity is required for activated microglias migration.

neuroscience↗

bioRxiv2021

Comprehensive analysis of RNA-seq and whole genome sequencing data reveals no evidence for SARS-CoV-2 integrating into host genome

SARS-CoV-2, as the causation of severe epidemic of COVID-19, is one kind of positive single-stranded RNA virus with high transmissibility. However, whether or not SARS-CoV-2 can integrate into host genome needs thorough investigation. Here, we performed both RNA sequencing (RNA-seq) and whole genome sequencing on SARS-CoV-2 infected human and monkey cells, and investigated the presence of host-virus chimeric events. Through RNA-seq, we did detect the chimeric host-virus reads in the infected cells. But further analysis using mixed libraries of infected cells and uninfected zebrafish embryos demonstrated that these reads are falsely generated during library construction. In support, whole genome sequencing also didnt identify the existence of chimeric reads in their corresponding regions. Therefore, the evidence for SARS-CoV-2s integration into host genome is lacking. One-Sentence SummarySARS-CoV-2 does not integrate into host genome through whole genome sequencing.

genomics↗

bioRxiv2021

Twelve-month specific IgG response to SARS-CoV-2 receptor-binding domain among COVID-19 convalescent plasma donors in Wuhan

To investigate the duration of humoral immune response in convalescent coronavirus disease 2019 (COVID-19) patients, we conduct a 12-month longitudinal study through collecting a total of 1,782 plasma samples from 869 convalescent plasma donors in Wuhan, China and test specific antibody responses. The results show that positive rate of IgG antibody against receptor-binding domain of spike protein (RBD-IgG) to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the COVID-19 convalescent plasma donors exceeded 70% for 12 months post diagnosis. The level of RBD-IgG decreases with time, with the titer stabilizing at 64.3% of the initial level by the 9th month. Moreover, male plasma donors produce more RBD-IgG than female, and age of the patients positively correlates with the RBD-IgG titer. A strong positive correlation between RBD-IgG and neutralizing antibody titers is also identified. These results facilitate our understanding of SARS-CoV-2-induced immune memory to promote vaccine and therapy development.

immunology↗

bioRxiv2020

TRIM28 regulates SARS-CoV-2 cell entry by targeting ACE2

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of coronavirus disease 2019 (COVID-19), it binds to angiotensin-converting enzyme 2 (ACE2) to enter into human cells. The expression level of ACE2 potentially determine the susceptibility and severity of COVID-19, it is thus of importance to understand the regulatory mechanism of ACE2 expression. Tripartite motif containing 28 (TRIM28) is known to be involved in multiple processes including antiviral restriction, endogenous retrovirus latency and immune response, it is recently reported to be co-expressed with SARS-CoV-2 receptor in type II pneumocytes; however, the roles of TRIM28 in ACE2 expression and SARS-CoV-2 cell entry remain unclear. This study showed that knockdown of TRIM28 induces ACE2 expression and increases pseudotyped SARS-CoV-2 cell entry of A549 cells and primary pulmonary alveolar epithelial cells (PAEpiCs). In a co-culture model of NK cells and lung epithelial cells, our results demonstrated that NK cells inhibit TRIM28 and promote ACE2 expression in lung epithelial cells, which was partially reversed by depletion of interleukin-2 and blocking of granzyme B in the co-culture medium. Furthermore, TRIM28 knockdown enhanced interferon-{gamma} (IFN-{gamma})-induced ACE2 expression through a mechanism involving upregulating IFN-{gamma} receptor 2 (IFNGR2) in both A549 and PAEpiCs. Importantly, the upregulated ACE2 induced by TRIM28 knockdown and co-culture of NK cells was partially reversed by dexamethasone in A549 cells but not PAEpiCs. Our study identified TRIM28 as a novel regulator of ACE2 expression and SARS-CoV-2 cell entry.

molecular biology↗

bioRxiv2020

Acquired mutations and transcriptional remodeling in long-term estrogen-deprived locoregional breast cancer recurrences

Endocrine therapy resistance is a hallmark of advanced estrogen receptor (ER) positive breast cancer. In this study, we performed DNA/RNA hybrid-capture sequencing on 12 locoregional recurrences after long-term estrogen-deprivation along with each tumors matched primary. Despite being up to 7 years removed from the primary lesion, most recurrences harbored similar intrinsic transcriptional and copy number profiles. Only two genes, AKAP9 and KMT2C, were found to have single nucleotide variant (SNV) enrichments in more than one recurrence. Enriched mutations in single cases included SNVs within transcriptional regulators such as ARID1A, TP53, FOXO1, BRD1, NCOA1 and NCOR2 with one local recurrence gaining three PIK3CA mutations. In contrast to DNA-level changes, we discovered recurrent outlier mRNA expression alterations were common--including outlier gains in TP63 (n=5 cases [42%]), NTRK3 [n=5 [42%]), NTRK2 (n=4 [33%]), PAX3 (n=4 [33%]), FGFR4 (n=3 [25%]) and TERT (n=3 [25%]). Recurrent losses involved ESR1 (n=5 [42%]), RELN (n=5 [42%]), SFRP4 (n=4 [33%]) and FOSB (n=4 [33%]). ESR1-depleted recurrences harbored shared transcriptional remodeling events including upregulation of PROM1 and other basal cancer markers. Taken together, this study defines acquired genomic changes in long-term, estrogen-deprived disease, highlights longitudinal RNA-profiling and identifies a common endocrine-resistant breast cancer subtype with basal-like transcriptional reprogramming.

cancer biology↗

bioRxiv2019

Targeting against HIV/HCV Co-infection using Machine Learning-based multitarget-quantitative structure-activity relationships (mt-QSAR) Methods

Co-infection between HIV-1 and HCV is common today in certain populations. However, treatment of co-infection is full of challenges with special consideration for potential hepatic safety and drug-drug interactions. Multitarget inhibitors with less toxicity may provide a promising therapeutic strategy for HIV/HCV co-infection. However, identification of one molecule acting on multiple targets simultaneously by experimental evaluation is costly and time-consuming. In silico target prediction tools provide more opportunities for the development of multitarget inhibitors. In this study, by combining naive Bayesian (NB) and support vector machine (SVM) algorithms with two types of molecular fingerprints (MACCS and ECFP6), 60 classification models were constructed to predict the active compounds toward 11 HIV-1 targets and 4 HCV targets based on the multitarget-quantitative structure-activity relationships (mt-QSAR). 5-fold cross-validation and test set validation was performed to confirm the performance of 60 classification models. Our results show that 60 mt-QSAR models appeared to have high classification accuracy in terms of ROC-AUC values ranging from 0.83 to 1 with a mean value of 0.97 for HIV-1 models, and ROC-AUC values ranging from 0.84 to 1 with a mean value of 0.96 for HCV. Furthermore, the 60 models were applied to comprehensively predict the potential targets for additional 46 compounds including 27 approved HIV-1 drugs, 10 approved HCV drugs and 9 selected compounds known to be active on one or more targets of HIV-1 or those of HCV. Finally, 18 hits including 7 HIV-1 approved drugs, 4 HCV approved drugs and 7 compounds were predicted to be HIV/HCV co-infection multitarget inhibitors. The reported bioactivity data confirmed that 7 compounds actually interacted with HIV-1 and HCV targets simultaneously with diverse binding affinities. Of those remaining predicted hits and chemical-protein interaction pairs involving the potential ability to suppress HIV/HCV co-infection deserve further investigation by experiments. This investigation shows that the mt-QSAR method is available to predict chemical-protein interaction for discovering multitarget inhibitors and provide a unique perspective on HIV/HCV co-infection treatment.

bioinformatics↗

bioRxiv2019

Proteomic and Transcriptomic Profiling Identifies Mediators of Anchorage-Independent Growth and Roles of Inhibitor of Differentiation Proteins in Invasive Lobular Breast Cancer

BACKGROUNDInvasive lobular carcinoma (ILC) is a histological subtype of breast cancer with distinct molecular and clinical features from the more common subtype invasive lobular carcinoma (IDC). We have previously shown that human ILC cells lines have a remarkably unique ability to grow in ultra-low attachment (ULA) suspension cultures as compared to IDC cells, the mediators of which remain unknown. METHODSUsing flow cytometry and immunoblotting in human ILC and IDC cell lines, we measured levels of apoptosis and cell proliferation in attached (2D) and suspension (ULA) cultures. siRNA-mediated knockdown and pharmacological inhibitors were utilized to assess the effects of known regulators of anchorage-independence. Reverse Phase Protein Arrays and RNA-Sequencing were performed to identify novel proteomic and transcriptomic mediators of ULA growth in ILC cells. RESULTSWe show that human ILC cell lines exhibit enhanced anoikis resistance and cell proliferation in ULA cultures as compared to IDC cells. Transient restoration of E-cadherin did not impact the 2D or ULA growth of human ILC cell lines, while transient E-cadherin knockdown in IDC cells partially rescued their growth defect in ULA culture. Inhibition of the Rho/ROCK, p120-catenin or YAP/Hippo pathways previously implicated in anoikis resistance did not have a major effect on the ULA growth of ILC cells. Proteomic comparison of ILC and IDC cell lines identified unique induction of PI3K/Akt and p90-RSK pathways in ULA culture in ILC cells. Transcriptional profiling uncovered unique upregulation of the Inhibitors of Differentiation family transcription factors ID1 and ID3 in ILC ULA culture, the knockdown of which diminished anchorage-independent growth. We find that ID1 and ID3 expression is higher in human ILC tumors as compared to IDC and correlated with a worse disease-specific survival uniquely in the ILC cohort. CONCLUSIONOur comprehensive study of 2D and ULA growth in human ILC cell lines revealed anoikis resistance, cell proliferation and novel mediators of anchorage-independence and provides possible mechanistic insights and clinical implications for metastatic dissemination of ILC. High expression in human ILC tumors and association with clinical outcome implicate ID1 and ID3 as novel drivers and therapeutic targets for lobular breast cancer.

cancer biology↗

bioRxiv2018

SmbHLH37 functions antagonistically with SmMYC2 in regulating jasmonate-mediated biosynthesis of phenolic acids in Salvia miltiorrhiza

Jasmonates (JAs) are integral to various defense responses and induce biosynthesis of many secondary metabolites. MYC2, a basic helix-loop-helix (bHLH) transcription factor (TF), acts as a transcriptional activator of JA signaling. MYC2 is repressed by the JASMONATE ZIM-domain (JAZ) proteins in the absence of JA, but de-repressed by the protein complex SCFCOI1 on perception of JA. We previously reported that overexpression of SmMYC2 promotes the production of salvianolic acid B (Sal B) in Salvia miltiorrhiza. However, the responsible molecular mechanism is unclear. Here, we showed that SmMYC2 binds to and activates the promoters of its target genes SmTAT1, SmPAL1, and SmCYP98A14 to activate Sal B accumulations. SmbHLH37, a novel bHLH gene significantly up-regulated by constitutive expression of SmMYC2, was isolated from S. miltiorrhiza for detailed functional characterization. SmbHLH37 forms a homodimer and interacts with SmJAZ3/8. Overexpression of SmbHLH37 substantially decreased yields of Sal B. SmbHLH37 binds to the promoters of its target genes SmTAT1 and SmPAL1 and blocks their expression to suppress the pathway for Sal B biosynthesis. These results indicate that SmbHLH37 negatively regulates JA signaling and functions antagonistically with SmMYC2 in regulating Sal B biosynthesis in S. miltiorrhiza.

plant biology↗