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On page 1 showing 1 ~ 20 papers out of 52 papers

Physiological and proteomic analyses of salt stress response in the halophyte Halogeton glomeratus.

  • Juncheng Wang‎ et al.
  • Plant, cell & environment‎
  • 2015‎

Very little is known about the adaptation mechanism of Chenopodiaceae Halogeton glomeratus, a succulent annual halophyte, under saline conditions. In this study, we investigated the morphological and physiological adaptation mechanisms of seedlings exposed to different concentrations of NaCl treatment for 21 d. Our results revealed that H. glomeratus has a robust ability to tolerate salt; its optimal growth occurs under approximately 100 mm NaCl conditions. Salt crystals were deposited in water-storage tissue under saline conditions. We speculate that osmotic adjustment may be the primary mechanism of salt tolerance in H. glomeratus, which transports toxic ions such as sodium into specific salt-storage cells and compartmentalizes them in large vacuoles to maintain the water content of tissues and the succulence of the leaves. To investigate the molecular response mechanisms to salt stress in H. glomeratus, we conducted a comparative proteomic analysis of seedling leaves that had been exposed to 200 mm NaCl for 24 h, 72 h and 7 d. Forty-nine protein spots, exhibiting significant changes in abundance after stress, were identified using matrix-assisted laser desorption ionization tandem time-of-flight mass spectrometry (MALDI-TOF/TOF MS/MS) and similarity searches across EST database of H. glomeratus. These stress-responsive proteins were categorized into nine functional groups, such as photosynthesis, carbohydrate and energy metabolism, and stress and defence response.


Comparative Proteomic Analysis of Cultured Suspension Cells of the Halophyte Halogeton glomeratus by iTRAQ Provides Insights into Response Mechanisms to Salt Stress.

  • Juncheng Wang‎ et al.
  • Frontiers in plant science‎
  • 2016‎

Soil salinity severely threatens land use capability and crop yields worldwide. An analysis of the molecular mechanisms of salt tolerance in halophytes will contribute to the development of salt-tolerant crops. In this study, a combination of physiological characteristics and iTRAQ-based proteomic approaches was conducted to investigate the molecular mechanisms underlying the salt response of suspension cell cultures of halophytic Halogeton glomeratus. These cells showed halophytic growth responses comparable to those of the whole plant. In total, 97 up-regulated proteins and 192 down-regulated proteins were identified as common to both 200 and 400 mM NaCl concentration treatments. Such salinity responsive proteins were mainly involved in energy, carbohydrate metabolism, stress defense, protein metabolism, signal transduction, cell growth, and cytoskeleton metabolism. Effective regulatory protein expression related to energy, stress defense, and carbohydrate metabolism play important roles in the salt-tolerance of H. glomeratus suspension cell cultures. However, known proteins regulating Na(+) efflux from the cytoplasm and its compartmentalization into the vacuole did not change significantly under salinity stress suggesting our existing knowledge concerning Na(+) extrusion and compartmentalization in halophytes needs to be evaluated further. Such data are discussed in the context of our current understandings of the mechanisms involved in the salinity response of the halophyte, H. glomeratus.


CCL18 promotes the metastasis of squamous cell carcinoma of the head and neck through MTDH-NF-κB signalling pathway.

  • Yuexiang Qin‎ et al.
  • Journal of cellular and molecular medicine‎
  • 2019‎

Metastasis is one of the primary causes for high mortality in patients with squamous cell carcinoma of the head and neck (SCCHN). Our previous study showed that chemokine (C-C motif) ligand 18 (CCL18), derived from tumour-associated macrophages (TAMs), regulates SCCHN metastasis by promoting epithelial-mesenchymal transition (EMT) and preserving stemness. However, the underlying mechanism needs to be further investigation. Interestingly, metadherin (MTDH) expression was induced when SCCHN cells were stimulated with recombinant CCL18 protein in this study. Suppressing MTDH expression reversed CCL18-induced migration, invasion and EMT in SCCHN cells. Furthermore, the NF-κB signalling pathway was involved in the MTDH knock-down cells with CCL18 stimulation. We performed ELISA to evaluate the CCL18 levels in the serums of 132 treatment-naive SCCHN patients, 25 patients with precancerous lesion and 32 healthy donors. Our results demonstrated that serum CCL18 levels were significantly higher in SCCHN patients than patients with precancerous lesion and healthy individuals. CCL18 levels were found to be significantly correlated with tumour classification, clinical stage, lymph node metastasis and histological grade in SCCHN patients. Thus, our findings suggest that CCL18 may serve as a potential biomarker for diagnosis of SCCHN and promote SCCHN invasion, migration and EMT by MTDH-NF-κB signalling pathway.


A novel inflammation-based nomogram system to predict survival of patients with hepatocellular carcinoma.

  • Jinbin Chen‎ et al.
  • Cancer medicine‎
  • 2018‎

The existed staging systems were limited in the accuracy of prediction for overall survival (OS) of hepatocellular carcinoma (HCC) patients. The aim of this study is to establish a novel inflammation-based prognostic system with nomogram for HCC patients.


Transcatheter arterial chemoembolization (TACE) versus hepatectomy in hepatocellular carcinoma with macrovascular invasion: a meta-analysis of 1683 patients.

  • Jinbin Chen‎ et al.
  • Journal of Cancer‎
  • 2017‎

For hepatocellular carcinoma (HCC) patients with macrovascular invasion (MaVI), hepatectomy and transcatheter arterial chemoembolization (TACE) remain the main treatment options in Asia. However, which could achieve better survivals remains controversial. In present study, we conducted a meta-analysis to clarify the survival benefits and safety of hepatectomy versus TACE in HCC patients with MaVI. The PubMed, Cochrane Library and Web of Science databases were searched for eligible studies. There were no prospective studies identified. 8 retrospective studies from Asia with 1683 patients met our inclusion criteria were included in meta-analysis. The overall survival (OS) is higher in hepatectomy group than TACE group (HR=1.61, 95%CI=1.23-2.10, p=0.0005). Hepatectomy was superior over TACE in 1-year (OR=2.27, 95%CI=1.26-4.08, p=0.006) and 3-year (OR=3.04, 95%CI=2.17-4.26, p<0.00001) respectively, but not in 5-year (OR=7.34, 95%CI=0.78-68.16, p=0.08) survival rate. Subgroup analysis demonstrated that hepatectomy was superior over TACE for patients with PVTT (HR=1.50, 95%CI=1.14-1.98, p=0.004), but not for patients with HVTT/IVC (HR=2.39, 95%CI=0.88-6.49, p=0.09). There was not significantly difference between two groups in peri-operative mortality. Our results indicated that, compared to TACE, hepatectomy might be a better treatment option for resectable HCC patients with MaVI. Being lack of high-quality studies, more well-designed multi-center randomized trials are needed to confirm our finding.


A Novel Role for Lymphotactin (XCL1) Signaling in the Nervous System: XCL1 Acts via its Receptor XCR1 to Increase Trigeminal Neuronal Excitability.

  • Emma V Bird‎ et al.
  • Neuroscience‎
  • 2018‎

Chemokines are known to have a role in the nervous system, influencing a range of processes including the development of chronic pain. To date there are very few studies describing the functions of the chemokine lymphotactin (XCL1) or its receptor (XCR1) in the nervous system. We investigated the role of the XCL1-XCR1 axis in nociceptive processing, using a combination of immunohistochemical, pharmacological and electrophysiological techniques. Expression of XCR1 in the rat mental nerve was elevated 3 days following chronic constriction injury (CCI), compared with 11 days post-CCI and sham controls. XCR1 co-existed with neuronal marker PGP9.5, leukocyte common antigen CD45 and Schwann cell marker S-100. In the trigeminal root and white matter of the brainstem, XCR1-positive cells co-expressed the oligodendrocyte marker Olig2. In trigeminal subnucleus caudalis (Vc), XCR1 immunoreactivity was present in the outer laminae and was colocalized with vesicular glutamate transporter 2 (VGlut2), but not calcitonin gene-related peptide (CGRP) or isolectin B4 (IB4). Incubation of brainstem slices with XCL1 induced activation of c-Fos, ERK and p38 in the superficial layers of Vc, and enhanced levels of intrinsic excitability. These effects were blocked by the XCR1 antagonist viral CC chemokine macrophage inhibitory protein-II (vMIP-II). This study has identified for the first time a role for XCL1-XCR1 in nociceptive processing, demonstrating upregulation of XCR1 at nerve injury sites and identifying XCL1 as a modulator of central excitability and signaling via XCR1 in Vc, a key area for modulation of orofacial pain, thus indicating XCR1 as a potential target for novel analgesics.


Integrative Transcriptomic and Proteomic Analyses of Molecular Mechanism Responding to Salt Stress during Seed Germination in Hulless Barley.

  • Yong Lai‎ et al.
  • International journal of molecular sciences‎
  • 2020‎

Hulless barley (Hordeum vulgare L. var. nudum) is one of the most important crops in the Qinghai-Tibet Plateau. Soil salinity seriously affects its cultivation. To investigate the mechanism of salt stress response during seed germination, two contrasting hulless barley genotypes were selected to first investigate the molecular mechanism of seed salinity response during the germination stage using RNA-sequencing and isobaric tags for relative and absolute quantitation technologies. Compared to the salt-sensitive landrace lk621, the salt-tolerant one lk573 germinated normally under salt stress. The changes in hormone contents also differed between lk621 and lk573. In lk573, 1597 differentially expressed genes (DEGs) and 171 differentially expressed proteins (DEPs) were specifically detected at 4 h after salt stress, and correspondingly, 2748 and 328 specifically detected at 16 h. Most specific DEGs in lk573 were involved in response to oxidative stress, biosynthetic process, protein localization, and vesicle-mediated transport, and most specific DEPs were assigned to an oxidation-reduction process, carbohydrate metabolic process, and protein phosphorylation. There were 96 genes specifically differentially expressed at both transcriptomic and proteomic levels in lk573. These results revealed the molecular mechanism of salt tolerance and provided candidate genes for further study and salt-tolerant improvement in hulless barley.


Molecular Mechanisms of Acclimatization to Phosphorus Starvation and Recovery Underlying Full-Length Transcriptome Profiling in Barley (Hordeum vulgare L.).

  • Panrong Ren‎ et al.
  • Frontiers in plant science‎
  • 2018‎

A lack of phosphorus (P) in plants can severely constrain growth and development. Barley, one of the earliest domesticated crops, is extensively planted in poor soil around the world. To date, the molecular mechanisms of enduring low phosphorus, at the transcriptional level, in barley are still unclear. In the present study, two different barley genotypes (GN121 and GN42)-with contrasting phosphorus efficiency-were used to reveal adaptations to low phosphorus stress, at three time points, at the morphological, physiological, biochemical, and transcriptome level. GN121 growth was less affected by phosphorus starvation and recovery than that of GN42. The biomass and inorganic phosphorus concentration of GN121 and GN42 declined under the low phosphorus-induced stress and increased after recovery with normal phosphorus. However, the range of these parameters was higher in GN42 than in GN121. Subsequently, a more complete genome annotation was obtained by correcting with the data sequenced on Illumina HiSeq X 10 and PacBio RSII SMRT platform. A total of 6,182 and 5,270 differentially expressed genes (DEGs) were identified in GN121 and GN42, respectively. The majority of these DEGs were involved in phosphorus metabolism such as phospholipid degradation, hydrolysis of phosphoric enzymes, sucrose synthesis, phosphorylation/dephosphorylation and post-transcriptional regulation; expression of these genes was significantly different between GN121 and GN42. Specifically, six and seven DEGs were annotated as phosphorus transporters in roots and leaves, respectively. Furthermore, a putative model was constructed relying on key metabolic pathways related to phosphorus to illustrate the higher phosphorus efficiency of GN121 compared to GN42 under low phosphorus conditions. Results from this study provide a multi-transcriptome database and candidate genes for further study on phosphorus use efficiency (PUE).


Comparative transcriptome analysis of genes involved in Na+ transport in the leaves of halophyte Halogeton glomeratus.

  • Juncheng Wang‎ et al.
  • Gene‎
  • 2018‎

Compartmentalization of Na+ into vacuoles is considered to be the most critical aspect of salt tolerance in H. glomeratus, an annual, succulent halophyte. Previous analysis of transcriptome involved in the H. glomeratus salt stress response relied on next-generation sequencing technologies that limit the capture of accurately spliced, full-length isoforms. To gain deeper insights into its salt stress response, we used the H. glomeratus Iso-Seq transcriptome database as a reference, and subsequent next-generation sequencing was subjected to various NaCl concentrations of leaves from plants revealed 115 upregulated and 87 downregulated differentially expressed isoforms (core DEIs). The majority of the core DEIs were involved in carbohydrate metabolism and energy production and conversion. In contrast, levels of known isoforms encoding Na+ transporters did not change significantly under salt stress. However, 16 core DEIs of unknown function were predicted to possess transmembrane domains, suggesting that these candidate isoforms could be involved in Na+ transport in H. glomeratus. These results suggest a potential means for identification of novel Na+ transporters, in addition to providing a foundation for further investigation of Na+ transport networks in halophytes.


MTDH associates with m6A RNA methylation and predicts cancer response for immune checkpoint treatment.

  • Fen Zhang‎ et al.
  • iScience‎
  • 2021‎

Immune checkpoint blockade (ICB) persistently provides a prognosis improvement but only in a small fraction of patients with cancer due to immunotherapy resistance induced by the consecutive activated oncogenic pathways, including MAPK, Akt, and WNT pathway partially driven by Metadherin (MTDH). However, there is no study to investigate the potential role and mechanisms of MTDH in ICB-treated cancers. Here, we systematically explored the cohorts from The Cancer Genome Atlas (TCGA) and independent cancer cohorts. Elevated MTDH expression was founded to associate with a worse overall survival and poorer immune response in patients with cancer. Dysregulated tumor-infiltrating immune cells and inhibitory immune checkpoint expression were correlated with MTDH expression. Furthermore, the mutual interactions between epithelial-to-mesenchymal-transition, m6A-RNA-methylation, and MTDH may illustrate the potential mechanisms of MTDH resistant to ICB treatment. Although more designed experiments and trials are needed in the future, targeting MTDH may help to overcome immunotherapy resistance in a wide range of cancers.


Liver Tumor Markers, HALP Score, and NLR: Simple, Cost-Effective, Easily Accessible Indexes for Predicting Prognosis in ICC Patients after Surgery.

  • Deyao Zhang‎ et al.
  • Journal of personalized medicine‎
  • 2022‎

To investigate the prognostic significance of liver tumor markers, the hemoglobin, albumin, lymphocyte, and platelet (HALP) score; neutrophil-to-lymphocyte ratio (NLR); and platelet-to-lymphocyte ratio (PLR), for predicting the specific site of recurrence or metastasis after surgery in patients with intrahepatic cholangiocarcinoma (ICC).


An integrated strategy for deciding open versus laparoscopic hepatectomy for resectable primary liver cancer.

  • Yizhen Fu‎ et al.
  • BMC cancer‎
  • 2023‎

Laparoscopic liver resection (LLR) is now widely performed in treating primary liver cancer (PLC) and yields equal long-term and superior short-term outcomes to those of open liver resection (OLR). The optimal surgical approach for resectable PLC (rPLC) remains controversial. Herein, we aimed to develop a nomogram to determine the most appropriate resection approach for the individual patient.


Structural insights into DNMT5-mediated ATP-dependent high-fidelity epigenome maintenance.

  • Juncheng Wang‎ et al.
  • Molecular cell‎
  • 2022‎

Epigenetic evolution occurs over million-year timescales in Cryptococcus neoformans and is mediated by DNMT5, the first maintenance type cytosine methyltransferase identified in the fungal or protist kingdoms, the first dependent on adenosine triphosphate (ATP), and the most hemimethyl-DNA-specific enzyme known. To understand these novel properties, we solved cryo-EM structures of CnDNMT5 in three states. These studies reveal an elaborate allosteric cascade in which hemimethylated DNA binding first activates the SNF2 ATPase domain by a large rigid body rotation while the target cytosine partially flips out of the DNA duplex. ATP binding then triggers striking structural reconfigurations of the methyltransferase catalytic pocket to enable cofactor binding, completion of base flipping, and catalysis. Bound unmethylated DNA does not open the catalytic pocket and is instead ejected upon ATP binding, driving high fidelity. This unprecedented chaperone-like, enzyme-remodeling role of the SNF2 ATPase domain illuminates how energy is used to enable faithful epigenetic memory.


Gain‑of‑function of IDO in DCs inhibits T cell immunity by metabolically regulating surface molecules and cytokines.

  • Fengge Wang‎ et al.
  • Experimental and therapeutic medicine‎
  • 2023‎

Both tolerogenicity and immunogenicity of dendritic cells (DCs) are regulated by their intracellular metabolism. As a rate-limiting enzyme of tryptophan (Trp) metabolism, indoleamine 2,3-dioxygenase (IDO) is involved in regulating the functions of numerous cell types, including DCs, a subset of which has a high capacity for producing IDO to control over-activated inflammation. To identify the mechanisms of IDO in DCs, stable DC lines with both gain- and reduction-of-function of IDO were established using a recombinant DNA technique. Although the IDO variation did not affect DC survival and migration, it altered Trp metabolism and other features of DCs analyzed by high-performance liquid chromatography and flow cytometry. On the surface of the DCs, IDO inhibited co-stimulatory CD86 but promoted co-inhibitory programmed cell death ligand 1 expression, and suppressed the antigen uptake, which ultimately led to the compromised ability of DCs to activate T cells. Furthermore, IDO also suppressed IL-12 secretion but enhanced that of IL-10 in DCs, which eventually induced T cells into tolerogenic phenotypes by inhibiting the differentiation of Th1 but promoting that of regulatory T cells. Collectively, the findings of the present study demonstrated that IDO is a key molecule for tolerogenic DC induction by metabolically regulating surface molecule and cytokine expression. This conclusion may lead to the targeted development of therapeutic drugs for autoimmune diseases.


REC114 Partner ANKRD31 Controls Number, Timing, and Location of Meiotic DNA Breaks.

  • Michiel Boekhout‎ et al.
  • Molecular cell‎
  • 2019‎

Double-strand breaks (DSBs) initiate the homologous recombination that is crucial for meiotic chromosome pairing and segregation. Here, we unveil mouse ANKRD31 as a lynchpin governing multiple aspects of DSB formation. Spermatocytes lacking ANKRD31 have altered DSB locations and fail to target DSBs to the pseudoautosomal regions (PARs) of sex chromosomes. They also have delayed and/or fewer recombination sites but, paradoxically, more DSBs, suggesting DSB dysregulation. Unrepaired DSBs and pairing failures-stochastic on autosomes, nearly absolute on X and Y-cause meiotic arrest and sterility in males. Ankrd31-deficient females have reduced oocyte reserves. A crystal structure defines a pleckstrin homology (PH) domain in REC114 and its direct intermolecular contacts with ANKRD31. In vivo, ANKRD31 stabilizes REC114 association with the PAR and elsewhere. Our findings inform a model in which ANKRD31 is a scaffold anchoring REC114 and other factors to specific genomic locations, thereby regulating DSB formation.


Transcriptome sequencing and comparative analysis of differentially-expressed isoforms in the roots of Halogeton glomeratus under salt stress.

  • Lirong Yao‎ et al.
  • Gene‎
  • 2018‎

Although Halogeton glomeratus (H. glomeratus) has been confirmed to have a unique mechanism to regulate Na+ efflux from the cytoplasm and compartmentalize Na+ into leaf vacuoles, little is known about the salt tolerance mechanisms of roots under salinity stress. In the present study, transcripts were sequenced using the BGISEQ-500 sequencing platform (BGI, Wuhan, China). After quality control, approximately 24.08 million clean reads were obtained and the average mapping ratio to the reference gene was 70.00%. When comparing salt-treated samples with the control, a total of 550, 590, 1411 and 2063 DEIs were identified at 2, 6, 24 and 72h, respectively. Numerous differentially-expressed isoforms that play important roles in response and adaptation to salt condition are related to metabolic processes, cellular processes, single-organism processes, localization, biological regulation, responses to stimulus, binding, catalytic activity and transporter activity. Fifty-eight salt-induced isoforms were common to different stages of salt stress; most of these DEIs were related to signal transduction and transporters, which maybe the core isoforms regulating Na+ uptake and transport in the roots of H. glomeratus. The expression patterns of 18 DEIs that were detected by quantitative real-time polymerase chain reaction were consistent with their respective changes in transcript abundance as identified by RNA-Seq technology. The present study thoroughly explored potential isoforms involved in salt tolerance on H. glomeratus roots at five time points. Our results may serve as an important resource for the H. glomeratus research community, improving our understanding of salt tolerance in halophyte survival under high salinity stress.


Pro-apoptotic effects of rHSG on C6 glioma cells.

  • Peng Gao‎ et al.
  • International journal of molecular medicine‎
  • 2016‎

Our previous in vitro study demonstrated that the rat hyperplasia suppressor gene (rHSG) inhibited the proliferation of C6 cells. In the present study, we investigated further the effects of rHSG overexpression on the apoptosis of C6 cells and the possible pathways involved. Hoechst 33342/PI double staining and comet assay were used to examine the morphological characteristics of apoptosis and to examine the effects of rHSG on the apoptosis of the C6 cells. Western blot analysis was used to determine the effects of rHSG overexpression on the protein expression levels of poly(ADP‑ribose) polymerase (PARP), cleaved caspase-3, phosphorylated extracellular signal-regulated kinase 1/2 (p-Erk1/2), phosphorylated Akt (p-Akt) and phosphoinositide 3-kinase (PI3K)/Akt, as well as on the mitogen-activated protein kinase (MAPK) pathways induced by insulin‑like growth factor (IGF)-1. Our results revealed that the C6 cells transfected with the rHSG adenoviral vector (Adv-rHSG-GFP group) efficiently expressed rHSG protein; Hoechst 33342/PI double staining and comet assay revealed that rHSG increased C6 cell apoptosis and induced DNA damage. Western blot analysis indicated that rHSG overexpression significantly increased the level of full-length PARP at 24 and 72 h (P<0.01), but decreased the level at 48 h following transfection (P<0.01), while the proteins levels of cleaved PARP and cleaved caspase-3 increased significantly (P<0.01). The protein expression of p-Erk1/2 and p-Akt began to decrease at 48 h post-transfection (P<0.01). In addition, the protein levels of Akt and Erk1/2 induced by IGF-1 were significantly inhibited. On the whole, the findings of the present study demonstrate that rHSG overexpression induces the apoptosis of rat glioma cells, and that these effects may involve the PI3K/Akt and MAPK pathways.


Oligomeric quaternary structure of Escherichia coli and Mycobacterium smegmatis Lhr helicases is nucleated by a novel C-terminal domain composed of five winged-helix modules.

  • Garrett M Warren‎ et al.
  • Nucleic acids research‎
  • 2021‎

Mycobacterium smegmatis Lhr (MsmLhr; 1507-aa) is the founder of a novel clade of bacterial helicases. MsmLhr consists of an N-terminal helicase domain (aa 1-856) with a distinctive tertiary structure (Lhr-Core) and a C-terminal domain (Lhr-CTD) of unknown structure. Here, we report that Escherichia coli Lhr (EcoLhr; 1538-aa) is an ATPase, translocase and ATP-dependent helicase. Like MsmLhr, EcoLhr translocates 3' to 5' on ssDNA and unwinds secondary structures en route, with RNA:DNA hybrid being preferred versus DNA:DNA duplex. The ATPase and translocase activities of EcoLhr inhere to its 877-aa Core domain. Full-length EcoLhr and MsmLhr have homo-oligomeric quaternary structures in solution, whereas their respective Core domains are monomers. The MsmLhr CTD per se is a homo-oligomer in solution. We employed cryo-EM to solve the structure of the CTD of full-length MsmLhr. The CTD protomer is composed of a series of five winged-helix (WH) modules and a β-barrel module. The CTD adopts a unique homo-tetrameric quaternary structure. A Lhr-CTD subdomain, comprising three tandem WH modules and the β-barrel, is structurally homologous to AlkZ, a bacterial DNA glycosylase that recognizes and excises inter-strand DNA crosslinks. This homology is noteworthy given that Lhr is induced in mycobacteria exposed to the inter-strand crosslinker mitomycin C.


Characterization of Glossy Spike Mutants and Identification of Candidate Genes Regulating Cuticular Wax Synthesis in Barley (Hordeum vulgare L.).

  • Xiuxiu Bian‎ et al.
  • International journal of molecular sciences‎
  • 2022‎

Cuticular waxes comprise the hydrophobic layer that protects crops against nonstomatal water loss and biotic and abiotic stresses. Expanding on our current knowledge of the genes that are involved in cuticular wax biosynthesis and regulation plays an important role in dissecting the processes of cuticular wax metabolism. In this study, we identified the Cer-GN1 barley (Hordeum vulgare L.) mutant that is generated by ethyl methanesulfonate mutagenesis with a glossy spike phenotype that is controlled by a single recessive nuclear gene. A physiological analysis showed that the total cuticular wax loads of Cer-GN1 were one-third that of the progenitor wild-type (WT), and its water loss rate was significantly accelerated (p < 0.05). In addition, Cer-GN1 was defective in the glume’s cuticle according to the toluidine blue dye test, and it was deficient in the tubule-shaped crystals which were observed on the glume surfaces by scanning electron microscopy. Using metabolomics and transcriptomics, we investigated the impacts of cuticular wax composition and waxy regulatory genes on the loss of the glaucous wax in the spikes of Cer-GN1. Among the differential metabolites, we found that 16-hydroxyhexadecanoic acid, which is one of the predominant C16 and C18 fatty acid-derived cutin monomers, was significantly downregulated in Cer-GN1 when it was compared to that of WT. We identified two novel genes that are located on chromosome 4H and are downregulated in Cer-GN1 (HvMSTRG.29184 and HvMSTRG.29185) that encode long-chain fatty acid omega-monooxygenase CYP704B1, which regulates the conversion of C16 palmitic acid to 16-hydroxyhexadecanoic acid. A quantitative real-time PCR revealed that the expression levels of HvMSTRG.29184 and HvMSTRG.29185 were downregulated at 1, 4, 8, 12, and 16 days after the heading stage in Cer-GN1 when it was compared to those of WT. These results suggested that HvMSTRG.29184 and HvMSTRG.29185 have CYP704B1 activity, which could regulate the conversion of C16 palmitic acid to 16-hydroxyhexadecanoic acid in barley. Their downregulation in Cer-GN1 reduced the synthesis of the cuticular wax components and ultimately caused the loss of the glaucous wax in the spikes. It is necessary to verify whether HvMSTRG.29184 and HvMSTRG.29185 truly encode a CYP704B1 that regulates the conversion of C16 palmitic acid to 16-hydroxyhexadecanoic acid in barley.


Molecular mechanisms of assembly and TRIP13-mediated remodeling of the human Shieldin complex.

  • Wei Xie‎ et al.
  • Proceedings of the National Academy of Sciences of the United States of America‎
  • 2021‎

The Shieldin complex, composed of REV7, SHLD1, SHLD2, and SHLD3, protects DNA double-strand breaks (DSBs) to promote nonhomologous end joining. The AAA+ ATPase TRIP13 remodels Shieldin to regulate DNA repair pathway choice. Here we report crystal structures of human SHLD3-REV7 binary and fused SHLD2-SHLD3-REV7 ternary complexes, revealing that assembly of Shieldin requires fused SHLD2-SHLD3 induced conformational heterodimerization of open (O-REV7) and closed (C-REV7) forms of REV7. We also report the cryogenic electron microscopy (cryo-EM) structures of the ATPγS-bound fused SHLD2-SHLD3-REV7-TRIP13 complexes, uncovering the principles underlying the TRIP13-mediated disassembly mechanism of the Shieldin complex. We demonstrate that the N terminus of REV7 inserts into the central channel of TRIP13, setting the stage for pulling the unfolded N-terminal peptide of C-REV7 through the central TRIP13 hexameric channel. The primary interface involves contacts between the safety-belt segment of C-REV7 and a conserved and negatively charged loop of TRIP13. This process is mediated by ATP hydrolysis-triggered rotatory motions of the TRIP13 ATPase, thereby resulting in the disassembly of the Shieldin complex.


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