A novel protein, Pho92, has a conserved YTH domain and regulates phosphate metabolism by decreasing the mRNA stability of PHO4 in Saccharomyces cerevisiae.

The homologue of human YTHDF2, Ydr374c (Pho92), is the only protein that has a YTH (YT521-B homology) domain in Saccharomyces cerevisiae. Based on microarray analysis, genes involved in the phosphate signal transduction (PHO) pathway were up-regulated in the Δpho92 strain, as were genes regulated by Pho4, which is an important transcription factor in the PHO pathway. To identify the exact mechanism of Pho92 action with respect to phosphate metabolism, we investigated the effect of Pho92 on PHO4 expression. The half-life of PHO4 mRNA was increased in the Δpho92 strain; this phenotype was also observed in the deletion mutants UPF1 and POP2, which are components of the NMD (nonsense-mediated decay) pathway and the Pop2-Ccr4-Not deadenylase complex respectively. Pho92 interacts physically with Pop2 of the Pop2-Ccr4-Not deadenylase complex. Furthermore, Pho92 binding to the 3'-UTR of PHO4 was dependent on the phosphate concentration. Deletion of the PHO4 3'-UTR resulted in PHO4 mRNA resistance to Pho92-dependent degradation. The results of the present study indicate that Pho92 regulates Pho4 expression at the post-transcriptional level via the regulation of mRNA stability. Taken together, Pho92 participates in cellular phosphate metabolism, specifically via the regulation of PHO4 mRNA stability by binding to the 3'-UTR in a phosphate-dependent manner.

The expression of PHO92 is regulated by Gcr1, and Pho92 is involved in glucose metabolism in Saccharomyces cerevisiae.

Ydr374c (Pho92) contains a YTH domain in its C-terminal region and is a human YTHDF2 homologue. Previously, we reported that Pho92 regulates phosphate metabolism by regulating PHO4 mRNA stability. In this study, we found that growth of the ∆pho92 strain on SG media was slower than that of the wild type and that PHO92 expression was up-regulated by non-fermentable carbon sources, such as ethanol and glycerol, but not by fermentable carbon sources. Furthermore, two conserved Gcr1-binding regions were identified in the upstream, untranslated region of PHO92. Gcr1 is an important factor involved in the coordinated regulation of glycolytic gene expression. Mutation of two Gcr1-binding sites of the PHO92 upstream region resulted in a growth defect on SD media. Finally, mutagenesis of the Gcr1-binding sites of the PHO92 upstream region and deletion of GCR1 resulted in up-regulation of PHO92, and this resulted from inhibition of PHO4 mRNA degradation. Based on these results, we suggest that Gcr1 regulates the expression of PHO92, and Pho92 is involved in glucose metabolism.

Rck1 up-regulates Hog1 activity by down-regulating Slt2 activity in Saccharomyces cerevisiae.

We previously reported that the over-expression of KDX1 up-regulates RCK1 gene expression. To further understand the function of Rck1, microarray analysis was performed using a RCK1 over-expressing strain. Based on microarray and Northern blot analyses, we determined that the expression of KDX1 was down-regulated when RCK1 was over-expressed. Furthermore, we determined that phosphorylated forms of Slt2 and Mkk2 were down-regulated by the over-expression of RCK1. Ptp2, a phosphatase that is regulated by the Slt2 MAP kinase pathway, was down-regulated by the over-expression of RCK1. Ptp2 is a negative regulator of Hog1; thus, the phosphorylated form of Hog1 was up-regulated by RCK1 over-expression. A point mutation of lysine 152 to arginine resulted in a failure to up-regulate Hog1 and the subsequent down-regulation of CTT1, which is a Hog1 pathway target gene. Furthermore, using microarray and Northern blot analyses, we determined that genes that are regulated by Msn2/Msn4 were up-regulated by Rck1 and that this was the result of Hog1 activation by RCK1 over-expression. Together, our results suggest that Rck1 inhibits Slt2 MAP kinase pathway activity and then Ptp2, which subsequently activates Hog1.

Kdx1 regulates RCK1 gene expression by interacting with Rlm1 in Saccharomyces cerevisiae.

Kdx1 is known as a stress-responsive protein. To better understand the function of Kdx1, we performed microarray analysis in KDX1 overexpressing cells and found that the overexpression of KDX1 dramatically induced the expression of RCK1, a stress-responsive gene. This result was confirmed by northern blot analysis. Furthermore, the overexpression of RCK1 partially rescued the growth defect caused by zymolyase stress. The expression of RCK1 was regulated independently by Slt2 and Hog1, and Kdx1 failed to induce the expression of RCK1 in a HOG1 deletion strain. The transcriptional factors Smp1, Sko1, Msn2, Msn4, and Hot1, which are regulated by Hog1, did not affect RCK1 expression, but Rlm1 did. Furthermore, the mutation of certain phosphorylation sites in RLM1 inhibited the induction of RCK1 expression by Kdx1. We found a conserved Rlm1 binding site in the 5' untranslated region (UTR) of RCK1, and the mutation of these Rlm1 binding sites also inhibited the induction of RCK1 expression by Kdx1. Finally, we showed that Kdx1 physically interacts with Rlm1 and that this interaction affects the ability of Rlm1 to bind to the RCK1 5' UTR. Taken together, these data suggest that Kdx1 interacts with Rlm1 to activate RCK1 gene expression in response to stress in Saccharomyces cerevisiae.

Cadmium inhibits the protein degradation of Sml1 by inhibiting the phosphorylation of Sml1 in Saccharomyces cerevisiae.

Cadmium is a toxic metal, and the mechanism of cadmium toxicity in living organisms has been well studied. Here, we used Saccharomyces cerevisiae as a model system to examine the detailed molecular mechanism of cell growth defects caused by cadmium. Using a plate assay of a yeast deletion mutant collection, we found that deletion of SML1, which encodes an inhibitor of Rnr1, resulted in cadmium resistance. Sml1 protein levels increased when cells were treated with cadmium, even though the mRNA levels of SML1 remained unchanged. Using northern and western blot analyses, we found that cadmium inhibited Sml1 degradation by inhibiting Sml1 phosphorylation. Sml1 protein levels increased when cells were treated with cadmium due to disruption of the dependent protein degradation pathway. Furthermore, cadmium promoted cell cycle progression into the G2 phase. The same result was obtained using cells in which SML1 was overexpressed. Deletion of SML1 delayed cell cycle progression. These results are consistent with Sml1 accumulation and with growth defects caused by cadmium stress. Interestingly, although cadmium treatment led to increase Sml1 levels, intracellular dNTP levels also increased because of Rnr3 upregulation due to cadmium stress. Taken together, these results suggest that cadmium specifically affects the phosphorylation of Sml1 and that Sml1 accumulates in cells.

Cd2+ binds to Atx1 and affects the physical interaction between Atx1 and Ccc2 in Saccharomyces cerevisiae.

The ATX1 deletion strain of Saccharomyces cerevisiae is more resistant to Cd(2+) than the wild-type. To investigate the function of Atx1 in Cd(2+) toxicity, we used a metal-binding assay to study the interaction between Atx1 and Cd(2+) in vitro. Using circular dichroism and two-hybrid analyses, we found that Atx1 can bind Cd(2+) specifically and that Cd(2+) binding to Atx1 affects the physical interaction between Atx1 and Ccc2. These results imply that Atx1 delivers Cd(2+) to Ccc2 and that this delivery is, at least in part, responsible for Cd(2+) toxicity in S. cerevisiae.

23-Hydroxytormentic acid and niga-ichgoside f1 isolated from Rubus coreanus attenuate cisplatin-induced cytotoxicity by reducing oxidative stress in renal epithelial LLC-PK1 cells.

The unripe fruits of Rubus coreanus (Rosaceae) are used in traditional Chinese medicine to relieve kidney dysfunction. In the present study, we evaluated the protective effects of the triterpenoid glycoside niga-ichigoside F1 (NIF1) and of its aglycone 23-hydroxytormentic acid (23-HTA) isolated from the unripe fruits of Rubus coreanus (Rosaceae) against cisplatin-induced cytotoxicity in renal epithelial LLC-PK1 cells. Pretreating LLC-PK1 cells with 23-HTA or NIF1 was found to prevent cisplatin-induced cytotoxicity and apoptosis. In addition, 23-HTA or NIF1 pretreatment significantly improved the changes associated with cisplatin toxicity by increasing levels of glutathione (GSH) and decreasing levels of malondialdehyde (MDA) and reactive oxygen species (ROS). The activity of antioxidant enzymes including catalase (CAT) and superoxide dismutase (SOD) was significantly lower in cisplatin-treated LL-PK1 cells, and 23-HTA or NIF1 treatment notably increased the these enzyme activity and protein and mRNA levels of CAT and manganese SOD (MnSOD). Moreover, cisplatin caused a significant decrease in nuclear levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and pretreatment with 23-HTA or NIF1 significantly suppressed the cisplatin-induced translocation of Nrf2 in LLC-PK1 cells. Taken together, these results suggest that 23-HTA ameliorates cisplatin-induced toxicity via modulation of antioxidant enzymes through activation of Nrf2 in LLC-PK1 cells.

Cadmium regulates copper homoeostasis by inhibiting the activity of Mac1, a transcriptional activator of the copper regulon, in Saccharomyces cerevisiae.

Cadmium is a toxic metal and the mechanism of its toxicity has been studied in various model systems from bacteria to mammals. We employed Saccharomyces cerevisiae as a model system to study cadmium toxicity at the molecular level because it has been used to identify the molecular mechanisms of toxicity found in higher organisms. cDNA microarray and Northern blot analyses revealed that cadmium salts inhibited the expression of genes related to copper metabolism. Western blotting, Northern blotting and chromatin immunoprecipitation experiments indicated that CTR1 expression was inhibited at the transcriptional level through direct inhibition of the Mac1 transcriptional activator. The decreased expression of CTR1 results in cellular copper deficiency and inhibition of Fet3 activity, which eventually impairs iron uptake. In this way, cadmium exhibits a negative effect on both iron and copper homoeostasis.

Genome editing of CCR5 by CRISPR-Cas9 in Mauritian cynomolgus macaque embryos.

The discovery that CCR5 serves as an R5-HIV-1 co-receptor, coupled with findings of protection from HIV infection in individuals lacking CCR5, led to the exploration of novel therapeutic strategies for HIV infection based on genome editing of CCR5. Advancing translation of CCR5-mutant-based cellular therapies for HIV requires development of novel physiologically relevant animal models. Mauritian cynomolgus macaques (MCMs), with high degree of MHC allele sharing, are valuable models for HIV-1 research and stem cell therapies. To facilitate the generation of a CCR5-mutant MHC-defined MCM model, we explored editing the CCR5 gene in MCM embryos via CRISPR-Cas9. We refined ovarian stimulation and in vitro fertilization (IVF) methods established for Chinese cynomolgus macaques to generate in vitro MCM embryos. Time-lapse embryo imaging was performed to assess the timing of MCM embryonic developmental events in control and CRISPR-Cas9 microinjected embryos. Using a dual-guide gene targeting approach, biallelic deletions in the CCR5 gene were introduced into ~ 23-37% of MCM embryos. In addition, single blastomere PCR analysis revealed mosaicism in CCR5 editing within the same embryo. Successful development of IVF and CCR5 editing protocols in MCM embryos lays a foundation for the creation of CCR5-mutant MCMs to assess novel stem cell-based HIV therapeutics.

A novel role for thioredoxin reductase in the iron metabolism of S. cerevisiae.

Intracellular levels of iron are tightly regulated. Saccharomyces cerevisiae uses well-defined pathways to extract iron molecules from the environment. Once inside the cell, the iron molecules must be transferred to target sites via an intracellular iron transporter. Although analogous carriers have been described for other metals, such as copper, an iron transporter has yet to be identified. We used two-dimensional gel electrophoresis and mass spectrometry techniques to attempt to identify the iron transporter from cytosolic fraction of S. cerevisiae. In this study, we identified the iron-binding activity of thioredoxin reductase, and our data suggest a potential role for this enzyme in intracellular iron transport.

Complete genome sequence of Planococcus faecalis AJ003T, the type species of the genus Planococcus and a microbial C30 carotenoid producer.

A novel type strain, Planococcus faecalis AJ003T, isolated from the feces of Antarctic penguins, synthesizes a rare C30 carotenoid, glycosyl-4,4'-diaponeurosporen-4'-ol-4-oic acid. The complete genome of P. faecalis AJ003T comprises a single circular chromosome (3,495,892 bp; 40.9% G + C content). Annotation analysis has revealed 3511 coding DNA sequences and 99 RNAs; seven genes associated with the MEP pathway and five genes involved in the carotenoid pathway have been identified. The functionality and complementation of 4,4'-diapophytoene synthase (CrtM) and two copies of heterologous 4,4'-diapophytoene desaturase (CrtN) involved in carotenoid biosynthesis were analyzed in Escherichia coli.

Metabolic engineering of the Stevia rebaudiana ent-kaurene biosynthetic pathway in recombinant Escherichia coli.

The ent-kaurene is a dedicated precursor pool and is responsible for synthesizing natural sweeteners such as steviol glycosides. In this study, to produce ent-kaurene in Escherichia coli, we modularly constructed and expressed two ent-kaurene genes encoding ent-copalyl diphosphate synthase (CPPS) and ent-kaurene synthase (KS) from Stevia rebaudiana known as a typical plant producing steviol glycoside. The CPPS and KS from S. rebaudiana were functionally expressed in a heterologous host E. coli. Furthermore, in order to enhance ent-kaurene production in E. coli, six geranylgeranyl diphosphate synthases (GGPPS) from various microorganisms and eight strains of E. coli as host were compared by measuring ent-kaurene production. The highest ent-kaurene production of approximately 41.1mg/L was demonstrated in E. coli strain MG1655 co-expressing synthetic CPPS-KS module and GGPPS from Rhodobacter sphaeroides. The ent-kaurene production was further increased up to 179.6 mg/L by overexpression of the three key enzymes for isoprenoid precursor, 1-deoxyxylulose-5-phosphate synthase (DXS), farnesyl diphosphate synthase (IspA) and isopentenyl diphosphate isomerase (IDI) from E. coli. Finally, the highest titer of ent-kaurene (578 mg/L) with a specific yield of ent-kaurene of 143.5mg/g dry cell weight was obtained by culturing E. coli strain MG1655 co-expressing the ent-kaurene module, DXS, IDI and IspA in 1L bioreactor containing 20 g/L glycerol.

Wireless Solar Water Splitting Device with Robust Cobalt-Catalyzed, Dual-Doped BiVO4 Photoanode and Perovskite Solar Cell in Tandem: A Dual Absorber Artificial Leaf.

A stand-alone, wireless solar water splitting device without external energy supply has been realized by combining in tandem a CH3NH3PbI3 perovskite single junction solar cell with a cobalt carbonate (Co-Ci)-catalyzed, extrinsic/intrinsic dual-doped BiVO4 (hydrogen-treated and 3 at% Mo-doped). The photoanode recorded one of the highest photoelectrochemical water oxidation activity (4.8 mA/cm(2) at 1.23 VRHE) under simulated 1 sun illumination. The oxygen evolution Co-Ci co-catalyst showed similar performance to best known cobalt phosphate (Co-Pi) (5.0 mA/cm(2) at 1.23 VRHE) on the same dual-doped BiVO4 photoanode, but with significantly better stability. A tandem artificial-leaf-type device produced stoichiometric hydrogen and oxygen with an average solar-to-hydrogen efficiency of 4.3% (wired), 3.0% (wireless) under simulated 1 sun illumination. Hence, our device based on a D4 tandem photoelectrochemical cell represents a meaningful advancement in performance and cost over the device based on a triple-junction solar cell-electrocatalyst combination.

Zedoarondiol isolated from the rhizoma of Curcuma heyneana is involved in the inhibition of iNOS, COX-2 and pro-inflammatory cytokines via the downregulation of NF-kappaB pathway in LPS-stimulated murine macrophages.

Several sesquiterpene lactones that have been isolated from medicinal plants are known to have many pharmacological activities. In this study, we investigated the anti-inflammatory effects of zedoarondiol, a sesquiterpene lactone isolated from the rhizoma of Curcuma heyneana, in lipopolysaccharide (LPS)-stimulated macrophage cells. Zedoarondiol dose-dependently inhibited LPS-stimulated nitric oxide (NO), prostaglandin E(2) (PGE(2)), tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and interleukin-1beta (IL-1beta) productions in RAW 264.7 macrophage and in mouse peritoneal macrophage cells. Consistent with these findings, in RAW 264.7 cells, zedoarondiol suppressed the LPS-stimulated protein levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) and the mRNA expressions of iNOS, COX-2, TNF-alpha, IL-6, and IL-1beta in a concentration-dependent manner. Moreover, molecular data revealed that zedoarondiol inhibited LPS-stimulated DNA binding activity and the transcription activity of nuclear factor-kappa B (NF-kappaB), and this effect was accompanied by decreases in the degradation and phosphorylation of inhibitory kappaB (IkappaB)-alpha, and in the subsequent blocking of NF-kappaB translocations to the nucleus. Furthermore, zedoarondiol attenuated the phosphorylations of IkappaB kinase (IKK), extracellular signal-regulated kinase (ERK), p38 mitogen-activated protein kinase (p38), and c-Jun N-terminal kinase (JNK) in LPS-stimulated RAW 264.7 cells. Taken together, the findings of the present study indicate that zedoarondiol inhibits iNOS, COX-2, and pro-inflammatory cytokine expressions by suppressing the phosphorylations of IKK and MAPKs, and by subsequently inactivating the NF-kappaB pathway. These relations reveal, in part, the mechanism underlying the anti-inflammatory properties of zedoarondiol.

Functional characterization of Hsp33 protein from Bacillus psychrosaccharolyticus; additional function of HSP33 on resistance to solvent stress.

Psychrophiles have been known as efficient organism to degrade organic solvent. To investigate the mechanism of solvent stress and identify the factors that affect the solvent stress in psychrophiles, we selected Bacillus psychrosaccharolyticus one of the psychrophiles and two-dimensional gel electrophoresis was performed. Among the protein spots analyzed by 2-DE, five spots induced in 3% IPA stress conditions were identified by MS/MS, and one of these spots was identified as a Hsp33 family. The Hsp33 protein sequence of B. psychrosaccharolyticus exhibited a high similarity with the corresponding proteins of other bacteria. The Hsp33 protein of B. psychrosaccharolyticus has a highly conserved zinc-binding domain (CXCX, CXXC) that includes four cysteine residues in the C-terminus. In addition, the transcriptional induction of the HSP33 of B. psychrosaccharolyticus was confirmed by Northern blot analysis, and formation of free thiol linkage was induced under stress conditions such as exposure to solvents, heat-shock, and oxidative stress. Furthermore, over-expressed strains of HSP33 of B. psychrosaccharolyticus in Escherichia coli improved stress tolerance to the organic solvent when compared with the wild-type. These data suggest that the solvent stress condition was similar to heat-shock or oxidative stress, especially through the triggering of induction and activation of a redox-regulatory chaperone, Hsp33, and Hsp33 plays a critical role in the tolerance to stress.