HISTONE DEACETYLASE 9 transduces heat signal in plant cells.

Heat stress limits plant growth, development, and crop yield, but how plant cells precisely sense and transduce heat stress signals remains elusive. Here, we identified a conserved heat stress response mechanism to elucidate how heat stress signal is transmitted from the cytoplasm into the nucleus for epigenetic modifiers. We demonstrate that HISTONE DEACETYLASE 9 (HDA9) transduces heat signals from the cytoplasm to the nucleus to play a positive regulatory role in heat responses in Arabidopsis. Heat specifically induces HDA9 accumulation in the nucleus. Under heat stress, the phosphatase PP2AB'ß directly interacts with and dephosphorylates HDA9 to protect HDA9 from 26S proteasome-mediated degradation, leading to the translocation of nonphosphorylated HDA9 to the nucleus. This heat-induced enrichment of HDA9 in the nucleus depends on the nucleoporin HOS1. In the nucleus, HDA9 binds and deacetylates the target genes related to signaling transduction and plant development to repress gene expression in a transcription factor YIN YANG 1-dependent and -independent manner, resulting in rebalance of plant development and heat response. Therefore, we uncover an HDA9-mediated positive regulatory module in the heat shock signal transduction pathway. More important, this cytoplasm-to-nucleus translocation of HDA9 in response to heat stress is conserved in wheat and rice, which confers the mechanism significant implication potential for crop breeding to cope with global climate warming.

The regulation of chromatin configuration at AGAMOUS locus by LFR-SYD-containing complex is critical for reproductive organ development in Arabidopsis.

Switch defective/sucrose non-fermentable (SWI/SNF) chromatin remodeling complexes are evolutionarily conserved, multi-subunit machinery that play vital roles in the regulation of gene expression by controlling nucleosome positioning and occupancy. However, little is known about the subunit composition of SPLAYED (SYD)-containing SWI/SNF complexes in plants. Here, we show that the Arabidopsis thaliana Leaf and Flower Related (LFR) is a subunit of SYD-containing SWI/SNF complexes. LFR interacts directly with multiple SWI/SNF subunits, including the catalytic ATPase subunit SYD, in vitro and in vivo. Phenotypic analyses of lfr-2 mutant flowers revealed that LFR is important for proper filament and pistil development, resembling the function of SYD. Transcriptome profiling revealed that LFR and SYD shared a subset of co-regulated genes. We further demonstrate that the LFR and SYD interdependently activate the transcription of AGAMOUS (AG), a C-class floral organ identity gene, by regulating the occupation of nucleosome, chromatin loop, histone modification, and Pol II enrichment on the AG locus. Furthermore, the chromosome conformation capture (3C) assay revealed that the gene loop at AG locus is negatively correlated with the AG expression level, and LFR-SYD was functional to demolish the AG chromatin loop to promote its transcription. Collectively, these results provide insight into the molecular mechanism of the Arabidopsis SYD-SWI/SNF complex in the control of higher chromatin conformation of the floral identity gene essential to plant reproductive organ development.

EGR1 and EGR2 positively regulate plant ABA signaling by modulating the phosphorylation of SnRK2.2.

During abscisic acid (ABA) signaling, reversible phosphorylation controls the activity and accumulation of class III SNF1-RELATED PROTEIN KINASE 2s (SnRK2s). While protein phosphatases that negatively regulate SnRK2s have been identified, those that positively regulate ABA signaling through SnRK2s are less understood. In this study, Arabidopsis thaliana mutants of Clade E Growth-Regulating 1 and 2 (EGR1/2), which belong to the protein phosphatase 2C family, exhibited reduced ABA sensitivity in terms of seed germination, cotyledon greening, and ABI5 accumulation. Conversely, overexpression increased these ABA-induced responses. Transcriptomic data revealed that most ABA-regulated genes in egr1 egr2 plants were expressed at reduced levels compared with those in Col-0 after ABA treatment. Abscisic acid up-regulated EGR1/2, which interact directly with SnRK2.2 through its C-terminal domain I. Genetic analysis demonstrated that EGR1/2 function through SnRK2.2 during ABA response. Furthermore, SnRK2.2 de-phosphorylation by EGR1/2 was identified at serine 31 within the ATP-binding pocket. A phospho-mimic mutation confirmed that phosphorylation at serine 31 inhibited SnRK2.2 activity and reduced ABA responsiveness in plants. Our findings highlight the positive role of EGR1/2 in regulating ABA signaling, they reveal a new mechanism for modulating SnRK2.2 activity, and provide novel insight into how plants fine-tune their responses to ABA.

Heat Shock Factor A1s are required for phytochrome-interacting factor 4-mediated thermomorphogenesis in Arabidopsis.

Thermomorphogenesis and the heat shock (HS) response are distinct thermal responses in plants that are regulated by PHYTOCHROME-INTERACTING FACTOR 4 (PIF4) and HEAT SHOCK FACTOR A1s (HSFA1s), respectively. Little is known about whether these responses are interconnected and whether they are activated by similar mechanisms. An analysis of transcriptome dynamics in response to warm temperature (28°C) treatment revealed that 30 min of exposure activated the expression of a subset of HSFA1 target genes in Arabidopsis thaliana. Meanwhile, a loss-of-function HSFA1 quadruple mutant (hsfa1-cq) was insensitive to warm temperature-induced hypocotyl growth. In hsfa1-cq plants grown at 28°C, the protein and transcript levels of PIF4 were greatly reduced, and the circadian rhythm of many thermomorphogenesis-related genes (including PIF4) was disturbed. Additionally, the nuclear localization of HSFA1s and the binding of HSFA1d to the PIF4 promoter increased following warm temperature exposure, whereas PIF4 overexpression in hsfa1-cq partially rescued the altered warm temperature-induced hypocotyl growth of the mutant. Taken together, these results suggest that HSFA1s are required for PIF4 accumulation at a warm temperature, and they establish a central role for HSFA1s in regulating both thermomorphogenesis and HS responses in Arabidopsis.

Ultrafine Co-Species Interspersed g-C3N4 Nanosheets and Graphene as an Efficient Polysulfide Barrier to Enable High Performance Li-S Batteries.

Lithium-sulfur (Li-S) batteries are regarded as one of the promising advanced energy storage systems due to their ultrahigh capacity and energy density. However, their practical applications are still hindered by the serious shuttle effect and sluggish reaction kinetics of soluble lithium polysulfides. Herein, g-C3N4 nanosheets and graphene decorated with an ultrafine Co-species nanodot heterostructure (Co@g-C3N4/G) as separator coatings were designed following a facile approach. Such an interlayer can not only enable effective polysulfide affinity through the physical barrier and chemical binding but also simultaneously have a catalytic effect on polysulfide conversion. Because of these superior merits, the Li-S cells assembled with Co@g-C3N4/G-PP separators matched with the S/KB composites (up to ~70 wt% sulfur in the final cathode) exhibit excellent rate capability and good cyclic stability. A high specific capacity of ~860 mAh g-1 at 2.0 C as well as a capacity-fading rate of only ~0.035% per cycle over 350 cycles at 0.5 C can be achieved. This bifunctional separator can even endow a Li-S cell at a low current density to exhibit excellent cycling capability, with a capacity retention rate of ~88.4% at 0.2 C over 250 cycles. Furthermore, a Li-S cell with a Co@g-C3N4/G-PP separator possesses a stable specific capacity of 785 mAh g-1 at 0.2 C after 150 cycles and a superior capacity retention rate of ~84.6% with a high sulfur loading of ~3.0 mg cm-2. This effective polysulfide-confined separator holds good promise for promoting the further development of high-energy-density Li-S batteries.

Rational Design of a Highly Dispersed Fe-N-C Nanosheet with 1,10-Phenanthroline-2,9-Dicarboxylic Acid as a Preorganized Ligand: Boosted Electrochemiluminescence Detection of Tetracycline.

In view of the shortcomings of the current coreactant electrochemiluminescence (ECL) and inspired by natural oxygen (O2) reduction metalloenzymes, a novel ECL amplification strategy was established. A pyrolytic iron- and nitrogen-doped (Fe-N-C) nanosheet rich in singly ionized oxygen vacancy (VO•) defects was rationally designed by destroying the highly saturated coordination with a preorganized ligand 1,10-phenanthroline-2,9-dicarboxylic acid (PDA). Extraordinary catalytic activity for O2 activation was obtained via screening a special pyrolysis temperature using spectroscopic and electrochemical methods. The high-spin ferric centers of highly dispersed FeC nanoclusters and abundant carbon and oxygen vacancy defects fully contributed to the inherent catalytic activity. ECL amplification was achieved by integrating the material with luminol to generate redox-active radicals in situ from dissolved O2 and simultaneously shorten the transferring distance of radicals. Tetracycline (TC), which posed a growing threat to aquatic biodiversity and environmental safety, as a model antibiotic was successfully detected with a detection limit of 3.88 nM (S/N = 3), clarifying a promising application prospect of this new effective ECL amplification strategy in biological analysis and environmental monitoring.

Transcriptional Profiling Reveals a Time-of-Day-Specific Role of REVEILLE 4/8 in Regulating the First Wave of Heat Shock-Induced Gene Expression in Arabidopsis.

Although much is known about plant responses to heat shock (HS), how plants sense high temperature and the primary HS signal transduction pathway leading to HS-regulated gene expression are still poorly understood. To identify primary transcription factors that mediate HS-regulated gene expression and their target genes, RNA sequencing was performed to detect genes whose expression is rapidly altered by HS in Arabidopsis (Arabidopsis thaliana). The results showed several genes were induced after only 5 min of HS treatment, suggesting that HS signaling occurs very rapidly. Analysis of the cis-elements in the promoters of genes upregulated by 10 min of HS treatment identified HEAT SHOCK FACTOR A1s (HSFA1s) and circadian clock proteins REVEILLE4 (RVE4) and RVE8 as essential transcription factors that independently mediate early HS-induced gene expression. Using hsfa1a/b/d/e and rve4/8 mutants, we identified subsets of HSFA1s- or RVE4/8-dependent early HS-induced genes and showed RVE4/8 regulate plant thermotolerance partially by regulating the expression of downstream transcription factors ETHYLENE RESPONSIVE FACTOR53 (ERF53) and ERF54, specifically around noon. These findings reveal a potential transcriptional regulatory hierarchy governing the first wave of HS-induced gene expression. They also provided important insight into the mechanism by which the circadian clock gates thermotolerance and prepares plants for exposure to high temperatures during the day.

Peroxisomal ß-oxidation regulates histone acetylation and DNA methylation in Arabidopsis.

Epigenetic markers, such as histone acetylation and DNA methylation, determine chromatin organization. In eukaryotic cells, metabolites from organelles or the cytosol affect epigenetic modifications. However, the relationships between metabolites and epigenetic modifications are not well understood in plants. We found that peroxisomal acyl-CoA oxidase 4 (ACX4), an enzyme in the fatty acid ß-oxidation pathway, is required for suppressing the silencing of some endogenous loci, as well as Pro35S:NPTII in the ProRD29A:LUC/C24 transgenic line. The acx4 mutation reduces nuclear histone acetylation and increases DNA methylation at the NOS terminator of Pro35S:NPTII and at some endogenous genomic loci, which are also targeted by the demethylation enzyme REPRESSOR OF SILENCING 1 (ROS1). Furthermore, mutations in multifunctional protein 2 (MFP2) and 3-ketoacyl-CoA thiolase-2 (KAT2/PED1/PKT3), two enzymes in the last two steps of the ß-oxidation pathway, lead to similar patterns of DNA hypermethylation as in acx4 Thus, metabolites from fatty acid ß-oxidation in peroxisomes are closely linked to nuclear epigenetic modifications, which may affect diverse cellular processes in plants.

UCN@Cs(6)-C82: An Encapsulated Triangular UCN Cluster with Ambiguous U Oxidation State [U(III) versus U(I)].

Understanding the chemical behavior of actinide elements is essential for the effective management and use of actinide materials. In this study, we report an unprecedented η2 (side-on) coordination of U by a cyanide in a UCN cluster, which was stabilized inside a C82 fullerene cage. UCN@Cs(6)-C82 was successfully synthesized and fully characterized by mass spectrometry, single crystal X-ray crystallography, cyclic voltammetry, spectroscopy, and theoretical calculations. The bonding analysis demonstrates significant donation bonding between CN- and uranium, and covalent interactions between uranium and the carbon cage. These effects correlate with an observed elongated cyanide C-N bond, resulting in a rare case where the oxidation state of uranium shows ambiguity between U(III) and U(I). The discovery of this unprecedented triangular configuration of the uranium cyanide cluster provides a new insight in coordination chemistry and highlights the large variety of bonding situations that uranium can have.

Wheat miR9678 Affects Seed Germination by Generating Phased siRNAs and Modulating Abscisic Acid/Gibberellin Signaling.

Seed germination is important for grain yield and quality and rapid, near-simultaneous germination helps in cultivation; however, cultivars that germinate too readily can undergo preharvest sprouting (PHS), which causes substantial losses in areas that tend to get rain around harvest time. Moreover, our knowledge of mechanisms regulating seed germination in wheat (Triticum aestivum) remains limited. In this study, we analyzed function of a wheat-specific microRNA 9678 (miR9678), which is specifically expressed in the scutellum of developing and germinating seeds. Overexpression of miR9678 delayed germination and improved resistance to PHS in wheat through reducing bioactive gibberellin (GA) levels; miR9678 silencing enhanced germination rates. We provide evidence that miR9678 targets a long noncoding RNA (WSGAR) and triggers the generation of phased small interfering RNAs that play a role in the delay of seed germination. Finally, we found that abscisic acid (ABA) signaling proteins bind the promoter of miR9678 precursor and activate its expression, indicating that miR9678 affects germination by modulating the GA/ABA signaling.

Histone acetyltransferase GCN5 contributes to cell wall integrity and salt stress tolerance by altering the expression of cellulose synthesis genes.

Excess soluble salts in soil are harmful to the growth and development of most plants. Evidence is emerging that the plant cell wall is involved in sensing and responding to salt stress, but the underlying mechanisms are not well understood. We reveal that the histone acetyltransferase General control non-repressed protein 5 (GCN5) is required for the maintenance of cell wall integrity and salt stress tolerance. The levels of GCN5 mRNA are increased in response to salt stress. The gcn5 mutants exhibited severe growth inhibition and defects in cell wall integrity under salt stress conditions. Combining RNA sequencing and chromatin immunoprecipitation assays, we identified the chitinase-like gene CTL1, polygalacturonase involved in expansion-3 (PGX3) and MYB domain protein-54 (MYB54) as direct targets of GCN5. Acetylation of H3K9 and H3K14 mediated by GCN5 is associated with activation of CTL1, PGX3 and MYB54 under salt stress. Moreover, constitutive expression of CTL1 in the gcn5 mutant restores salt tolerance and cell wall integrity. In addition, the expression of the wheat TaGCN5 gene in Arabidopsis gcn5 mutant plants complemented the salt tolerance and cell wall integrity phenotypes, suggesting that GCN5-mediated salt tolerance is conserved between Arabidopsis and wheat. Taken together, our data indicate that GCN5 plays a key role in the preservation of salt tolerance via versatile regulation in plants.

Heterologous expression of heat stress-responsive AtPLC9 confers heat tolerance in transgenic rice.

BACKGROUND: As global warming becomes increasingly severe, it is urgent that we enhance the heat tolerance of crops. We previously reported that Arabidopsis thaliana PHOSPHOINOSITIDE-SPECIFIC PHOSPHOLIPASE C9 (AtPLC9) promotes heat tolerance. RESULTS: In this study, we ectopically expressed AtPLC9 in rice to examine its potential to improve heat tolerance in this important crop. Whereas AtPLC9 did not improve rice tolerance to salt, drought or cold, transgenic rice did exhibit greater heat tolerance than the wild type. High-throughput RNA-seq revealed extensive and dynamic transcriptome reprofiling in transgenic plants after heat stress. Moreover, the expression of some transcription factors and calcium ion-related genes showed specific upregulation in transgenic rice after heat stress, which might contribute to the enhanced heat tolerance. CONCLUSIONS: This study provides preliminary guidance for using AtPLC9 to improve heat tolerance in cereal crops and, more broadly, highlights that heterologous transformation can assist with molecular breeding.

Wheat TaSPL8 Modulates Leaf Angle Through Auxin and Brassinosteroid Signaling.

In grass crops, leaf angle is determined by development of the lamina joint, the tissue connecting the leaf blade and sheath, and is closely related to crop architecture and yield. In this study, we identified a mutant generated by fast neutron radiation that exhibited an erect leaf phenotype caused by defects in lamina joint development. Map-based cloning revealed that the gene TaSPL8, encoding a SQUAMOSA PROMOTER BINDING-LIKE (SPL) protein, is deleted in this mutant. TaSPL8 knock-out mutants exhibit erect leaves due to loss of the lamina joint, compact architecture, and increased spike number especially in high planting density, suggesting similarity with its LIGULESS1 homologs in maize (Zea mays) and rice (Oryza sativa). Hence, LG1 could be a robust target for plant architecture improvement in grass species. Common wheat (Triticum aestivum, 2n = 6× = 42; BBAADD) is an allohexaploid containing A, B, and D subgenomes and the homeologous gene of TaSPL8 from the D subgenome contributes to the length of the lamina joint to a greater extent than that from the A and B subgenomes. Comparison of the transcriptome between the Taspl8 mutant and the wild type revealed that TaSPL8 is involved in the activation of genes related to auxin and brassinosteroid pathways and cell elongation. TaSPL8 binds to the promoters of the AUXIN RESPONSE FACTOR gene and of the brassinosteroid biogenesis gene CYP90D2 and activates their expression. These results indicate that TaSPL8 might regulate lamina joint development through auxin signaling and the brassinosteroid biosynthesis pathway.

Mutations in eIF5B Confer Thermosensitive and Pleiotropic Phenotypes via Translation Defects in Arabidopsis thaliana.

The conserved eukaryotic translation initiation factor 5B, eIF5B, is a GTPase that acts late in translation initiation. We found that an Arabidopsis thaliana mutant sensitive to hot temperatures 3 (hot3-1), which behaves as the wild type in the absence of stress but is unable to acclimate to high temperature, carries a missense mutation in the eIF5B1 gene (At1g76810), producing a temperature sensitive protein. A more severe, T-DNA insertion allele (hot3-2) causes pleiotropic developmental phenotypes. Surprisingly, Arabidopsis has three other eIF5B genes that do not substitute for eIF5B1; two of these appear to be in the process of pseudogenization. Polysome profiling and RNA-seq analysis of hot3-1 plants show delayed recovery of polysomes after heat stress and reduced translational efficiency (TE) of a subset of stress protective proteins, demonstrating the critical role of translational control early in heat acclimation. Plants carrying the severe hot3-2 allele show decreased TE of auxin-regulated, ribosome-related, and electron transport genes, even under optimal growth conditions. The hot3-2 data suggest that disrupting specific eIF5B interactions on the ribosome can, directly or indirectly, differentially affect translation. Thus, modulating eIF5B interactions could be another mechanism of gene-specific translational control.

Glycerol-Induced Powdery Mildew Resistance in Wheat by Regulating Plant Fatty Acid Metabolism, Plant Hormones Cross-Talk, and Pathogenesis-Related Genes.

Our previous study indicated that glycerol application induced resistance to powdery mildew (Bgt) in wheat by regulating two important signal molecules, glycerol-3-phosphate (G3P) and oleic acid (OA18:1). Transcriptome analysis of wheat leaves treated by glycerol and inoculated with Bgt was performed to identify the activated immune response pathways. We identified a set of differentially expressed transcripts (e.g., TaGLI1, TaACT1, and TaSSI2) involved in glycerol and fatty acid metabolism that were upregulated in response to Bgt infection and might contribute to G3P and OA18:1 accumulation. Gene Ontology (GO) enrichment analysis revealed GO terms induced by glycerol, such as response to jasmonic acid (JA), defense response to bacterium, lipid oxidation, and growth. In addition, glycerol application induced genes (e.g., LOX, AOS, and OPRs) involved in the metabolism pathway of linolenic and alpha-linolenic acid, which are precursor molecules of JA biosynthesis. Glycerol induced JA and salicylic acid (SA) levels, while glycerol reduced the auxin (IAA) level in wheat. Glycerol treatment also induced pathogenesis related (PR) genes, including PR-1, PR-3, PR-10, callose synthase, PRMS, RPM1, peroxidase, HSP70, HSP90, etc. These results indicate that glycerol treatment regulates fatty acid metabolism and hormones cross-talk and induces the expression of PR genes that together contribute to Bgt resistance in wheat.

Identification of a redox-dependent regulatory network of miRNAs and their targets in wheat.

Reactive oxygen species and antioxidants have an important role in the regulation of plant growth and development under both optimal and stress conditions. In this study, we investigate a possible redox control of miRNAs in wheat (Triticum aestivum ssp. aestivum). Treatment of seedlings with 10 mM H2O2 via the roots for 24 h resulted in decreased glutathione content, increased half-cell reduction potential of the glutathione disulphide/glutathione redox pair, and greater ascorbate peroxidase activity compared to the control plants. These changes were accompanied by alterations in the miRNA transcript profile, with 70 miRNAs being identified with at least 1.5-fold difference in their expression between control and treated (0, 3, 6 h) seedlings. Degradome sequencing identified 86 target genes of these miRNAs, and 6722 possible additional target genes were identified using bioinformatics tools. The H2O2-responsiveness of 1647 target genes over 24 h of treatment was also confirmed by transcriptome analysis, and they were mainly found to be related to the control of redox processes, transcription, and protein phosphorylation and degradation. In a time-course experiment (0-24 h of treatment) a correlation was found between the levels of glutathione, other antioxidants, and the transcript levels of the H2O2-responsive miRNAs and their target mRNAs. This relationship together with bioinformatics modelling of the regulatory network indicated glutathione-related redox control of miRNAs and their targets, which allows the adjustment of the metabolism to changing environmental conditions.

Genome-Wide Mapping of Targets of Maize Histone Deacetylase HDA101 Reveals Its Function and Regulatory Mechanism during Seed Development.

Histone deacetylases (HDACs) regulate histone acetylation levels by removing the acetyl group from lysine residues. The maize (Zea mays) HDACHDA101 influences several aspects of development, including kernel size; however, the molecular mechanism by which HDA101 affects kernel development remains unknown. In this study, we find that HDA101 regulates the expression of transfer cell-specific genes, suggesting that their misregulation may be associated with the defects in differentiation of endosperm transfer cells and smaller kernels observed in hda101 mutants. To investigate HDA101 function during the early stages of seed development, we performed genome-wide mapping of HDA101 binding sites. We observed that, like mammalian HDACs, HDA101 mainly targets highly and intermediately expressed genes. Although loss of HDA101 can induce histone hyperacetylation of its direct targets, this often does not involve variation in transcript levels. A small subset of inactive genes that must be negatively regulated during kernel development is also targeted by HDA101 and its loss leads to hyperacetylation and increased expression of these inactive genes. Finally, we report that HDA101 interacts with members of different chromatin remodeling complexes, such as NFC103/MSI1 and SNL1/SIN3-like protein corepressors. Taken together, our results reveal a complex genetic network regulated by HDA101 during seed development and provide insight into the different mechanisms of HDA101-mediated regulation of transcriptionally active and inactive genes.

Th@Td(19151)-C76: A Highly Symmetric Fullerene Cage Stabilized by a Tetravalent Actinide Metal Ion.

For the first time, Th@Td(19151)-C76, a highly symmetric C76 cage encapsulating an actinide metal ion, has been synthesized and characterized by single-crystal X-ray crystallography, mass spectrometry, UV-vis-NIR spectroscopy, and cyclic voltammetry. The single-crystal crystallographic analysis unambiguously assigned the fullerene cage as Td(19151)-C76 and confirmed Th@Td(19151)-C76 as the first IPR (isolated-pentagon rule) C76-based monometallofullerene. The crystallographic results further revealed that the optimal Th site resides over a sumanene-type hexagon, similar to that of the Th@C1(11)-C86 but different from the previously reported Th@C3v(8)-C82. In addition, electrochemical study found that Th@Td(19151)-C76 processes an unusually low first oxidation potential (0.03 V), suggesting its strong electron donating ability.

The SNP Rs915014 in MTHFR Regulated by MiRNA Associates with Atherosclerosis.

BACKGROUND/AIMS: The association between the genetic polymorphisms located in either the exon or untranslated region of MTHFR and the risk of human atherosclerosis has been well-documented. This study analyzed MTHFR polymorphisms at the 3'-untranslated region for association with risk and outcome of atherosclerosis in a Chinese Han population. METHODS: The hospital based case-control study was conducted with 500 patients and 600 healthy volunteers as control enrolled. The genotyping was conducted by using Taqman probe. The potential interaction was predicted by multiple bioinformatics analysis. The relative expression of MTHFR was detected by qRT-PCR. Further confirmation was determined by dual-luciferase assay. The plasma homocysteine levels were assayed by ELISA. RESULTS: Cigarette smoking, alcohol consumption, diabetes, hypertension and low levels of serum high-density lipoprotein-C were associated with an increased risk of developing ischemic stroke. MTHFR rs915014 AG and GG genotypes were significantly associated with increased risk of rs915014 compared with the GG genotype. The qRT-PCR confirmed that MTHFR rs915014 AG or GG genotypes could facilitate miR-2861 binding leading to decreased MTHFR levels in cells. In addition, patients carrying the MTHFR rs915014 AG or GG genotypes were associated with accumulation of circulating tHcy volume and a poor atherosclerosis consequence. CONCLUSIONS: This study demonstrates that the MTHFR rs915014 is associated with increased risk of atherosclerosis and might be a shot term outcome biomarker for atherosclerosis patients.

The E3 Ligase TaSAP5 Alters Drought Stress Responses by Promoting the Degradation of DRIP Proteins.

In Arabidopsis (Arabidopsis thaliana) plants growing under normal conditions, DEHYDRATION-RESPONSIVE ELEMENT BINDING PROTEIN2A (DREB2A) is present at low levels because it is ubiquitinated and destabilized by DREB2A INTERACTING PROTEIN1 (DRIP1) and DRIP2 through 26S proteasome-mediated proteolysis. Drought stress counteracts the ubiquitination and proteolysis of DREB2A, thus allowing the accumulation of sufficient amounts of DREB2A protein to activate downstream gene expression. The mechanisms leading to drought stress-mediated DREB2A accumulation are still unclear. Here, we report that the wheat (Triticum aestivum) TaSAP5 protein, which contains an A20/AN1 domain, acts as an E3 ubiquitin ligase to mediate DRIP degradation and thus increase DREB2A protein levels. Drought induces TaSAP5 expression in wheat, and TaSAP5 overexpression in Arabidopsis and wheat seedlings increased their drought tolerance, as measured by survival rate and grain yield under severe drought stress. TaSAP5 can interact with and ubiquitinate TaDRIP, as well as AtDRIP1 and AtDRIP2, leading to their subsequent degradation through the 26S proteasome pathway. Consistent with this, TaSAP5 overexpression enhances DRIP degradation and increases the levels of DREB2A protein and its downstream targets. These results suggest that TaSAP5 acts to link drought with DREB2A accumulation and illustrate the molecular mechanisms involved in this process.