Recent advances in long non-coding RNA of yeast / 医学研究生学报

Long non-coding RNA is a kind of functional RNA molecule which is widely existed in organisms and does not encode proteins. It plays a role directly at the RNA level and affects the life activities of organisms. With the development of research technology, the research on long non-coding RNA in fungi has been increasing steadily. This article mainly classifies long non-coding RNAs in Saccharomyces cerevisiae and Schizosaccharomyces pombe, and describes their mode of action and the biological functions they participate in, in order to provide some theory and further research for yeast long non-coding RNA research foundation.

Bacillus sp. SAB E-41-derived extract shows antiaging properties via ctt1-mediated oxidative stress tolerance response in yeast Schizosaccharomyces pombe

Objective: To analyze potential activation of oxidative stress tolerance systems by SAB E-41 bacterial extract in promoting the life span of yeast Schizosaccharomyces pombe. Methods: In vitro analysis was done to assess antioxidant activity of SAB E-41 bacterial extract. Antiaging property of the particular extract was then assayed through spot test and chronological life span assays. Furthermore, sty1 mitogen-activated protein kinase, pap1 transcriptional factor of oxidative stress response and its downstream genes, ctt1 were evaluated via real time PCR. The protein level of ctt1 was then observed via Western Blot analysis. In addition, accumulation of reactive oxygen species and mitochondrial activity were conducted to understand the effect of SAB E-41 upon oxidative stress response systems in vivo. Results: The IC50 values of corresponding extract for antioxidant (DPPH; ABTS) and antiglycation were 402.40, 358.13 and 683.55 μg/mL, respectively. In addition, SAB E-41 extract (750 μg/mL) exhibited antiaging properties, which could be attributed to significant up-regulation of oxidative stress response genes, sty1, pap1 and ctt1. Interestingly, SAB E-41 extract could enhance stress tolerance phenotype of Schizosaccharomyces pombe against H2O2-induced oxidative stress. These results were supported by increasing mitochondrial activity and reactive oxygen species intracellular levels. Conclusions: SAB E-41 extract could promote yeast life span likely via up-regulation of oxidative stress responses in yeast. Our results suggest that adaptive response via up-regulation of oxidative stress transcriptional factors, and its downstream gene, ctt1, as well as mitochondrial activity contributes in combating oxidative stress thus promoting yeast life span.

LAMMER Kinase Lkh1 Is an Upstream Regulator of Prk1-Mediated Non-Sexual Flocculation in Fission Yeast

The cation-dependent galactose-specific flocculation activity of the Schizosaccharomyces pombe null mutant of lkh1⁺, the gene encoding LAMMER kinase homolog, has previously been reported by our group. Here, we show that disruption of prk1⁺, another flocculation associated regulatory kinase encoding gene, also resulted in cation-dependent galactose-specific flocculation. Deletion of prk1 increased the flocculation phenotype of the lkh1⁺ null mutant and its overexpression reversed the flocculation of cells caused by lkh1 deletion. Transcript levels of prk1⁺ were also decreased by lkh1⁺ deletion. Cumulatively, these results indicate that Lkh1 is one of the negative regulators acting upstream of Prk1, regulating non-sexual flocculation in fission yeast.

Bacillus sp. SAB E-41-derived extract shows antiaging properties via ctt1-mediated oxidative stress tolerance response in yeast Schizosaccharomyces pombe

Objective: To analyze potential activation of oxidative stress tolerance systems by SAB E-41 bacterial extract in promoting the life span of yeast Schizosaccharomyces pombe. Methods: In vitro analysis was done to assess antioxidant activity of SAB E-41 bacterial extract. Antiaging property of the particular extract was then assayed through spot test and chronological life span assays. Furthermore, sty1 mitogen-activated protein kinase, pap1 transcriptional factor of oxidative stress response and its downstream genes, ctt1 were evaluated via real time PCR. The protein level of ctt1 was then observed via Western Blot analysis. In addition, accumulation of reactive oxygen species and mitochondrial activity were conducted to understand the effect of SAB E-41 upon oxidative stress response systems in vivo. Results: The IC

Chromosomal context and replication properties of ARS plasmids in Schizosaccharomyces pombe.

Short, specific DNA sequences called as Autonomously Replicating Sequence (ARS) elements function as plasmid as well as chromosomal replication origins in yeasts. As compared to ARSs, different chromosomal origins vary greatly in their efficiency and timing of replication probably due to their wider chromosomal context. The two Schizosaccharomyces pombe ARS elements, ars727 and ars2004, represent two extremities in their chromosomal origin activity – ars727 is inactive and late replicating, while ars2004 is a highly active, early-firing origin. To determine the effect of chromosomal context on the activity of these ARS elements, we have cloned them with their extended chromosomal context as well as in the context of each other in both orientations and analysed their replication efficiency by ARS and plasmid stability assays. We found that these ARS elements retain their origin activity in their extended/altered context. However, deletion of a 133-bp region of the previously reported ars727- associated late replication enforcing element (LRE) caused advancement in replication timing of the resulting plasmid. These results confirm the role of LRE in directing plasmid replication timing and suggest that the plasmid origin efficiency of ars2004 or ars727 remains unaltered by the extended chromosomal context.

Screening Molecular Chaperones Similar to Small Heat Shock Proteins in Schizosaccharomyces pombe

To screen molecular chaperones similar to small heat shock proteins (sHsps), but without alpha-crystalline domain, heat-stable proteins from Schizosaccharomyces pombe were analyzed by 2-dimensional electrophoresis and matrix assisted laser desorption/ionization time-of-flight mass spectrometry. Sixteen proteins were identified, and four recombinant proteins, including cofilin, NTF2, pyridoxin biosynthesis protein (Snz1) and Wos2 that has an alpha-crystalline domain, were purified. Among these proteins, only Snz1 showed the anti-aggregation activity against thermal denaturation of citrate synthase. However, pre-heating of NTF2 and Wos2 at 70degrees C for 30 min, efficiently prevented thermal aggregation of citrate synthase. These results indicate that Snz1 and NTF2 possess molecular chaperone activity similar to sHsps, even though there is no alpha-crystalline domain in their sequences.

Possible Roles of LAMMER Kinase Lkh1 in Fission Yeast by Comparative Proteome Analysis

To investigate the possible roles of LAMMER kinase homologue, Lkh1, in Schizosaccharomyces pombe, whole proteins were extracted from wild type and lkh1-deletion mutant cells and subjected to polyacrylamide gel electrophoresis. Differentially expressed proteins were identified by tandem mass spectrometry (MS/MS) and were compared with a protein database. In whole-cell extracts, 10 proteins were up-regulated and 9 proteins were down-regulated in the mutant. In extracellular preparations, 6 proteins were up-regulated in the lkh1 + null mutant and 4 proteins successfully identified: glycolipid anchored surface precursor, beta-glucosidase (Psu1), cell surface protein, glucan 1,3-beta-glucosidase (Bgl2), and exo-1,3 beta-glucanase (Exg1). These results suggest that Lkh1 is involved in regulating cell wall assembly.

HIV-1 Vif Protein Mediates the Degradation of APOBEC3G in Fission Yeast When Over-expressed Using Codon Optimization / 中国病毒学·英文版

Interaction between the HIV-1 Vif protein and the cellular host APOBEC3G protein is a promising target for inhibition of HIV-1 replication. Considering that human cells are a very complicated environment for the study of protein interactions, the goal of this study was to check whether fission yeast could be used as a model cell for studying the Vif-APOBEC3G interaction. Vif and APOBEC3G were expressed in fusion with GFP protein in the S. pombe SP223 strain. Subcellular localizations of Vif and APOBEC3G were observed with fluorescent microscopy. Codon optimization was used to over express the Vif protein in S. pombe cells. The degradation of APOBEC3G mediated by Vif was tested through expressing Vif and GFP-APOBEC3G proteins in the same cell. Western Blot analysis was used to measure the corresponding protein levels under different experimental conditions. The results showed that the Vif protein was predominantly localized in the nucleus of S.pombe cells, APOBEC3G was localized in the cytoplasm and concentrated at punctate bodies that were often in close proximity to the nucleus but were not necessarily restricted from other regions in the cytoplasm. Vif protein expression levels were increased significantly by using codon optimization and APOBEC3G was degraded when Vif was over-expressed in the same S. pombe cells. These results indicate that fission yeast is a good model for studying the interaction between the Vif and APOBEC3G proteins.

Study of the inhibition mechanism of edelfosine on cytokinesis in Schizosaccharomyces pombe / 中国药理学通报

Aim To Study the inhibition mechanism of edelfosine on cytokinesis in Schizosaccharomyces pombe. Methods To observe the inhibition of cytokinesis and growth, the experiments of inhibition of cyto-kinesis and parallel growth were carried out. To explore the inhibition mechanism of edelfosine, the experiment of retransfection of yeast genes was carried out. Results Edelfosine inhibited the cytokinesis of S.pombe in low dosage and cell growth in high dosage. The mid2△、spm1△ and pmp1△ strains were resistant to edelfosine in high dosage. However, these strains retrieved the sensitive to edelfosine in high dosage by retransfected the relevant genes, respectively. A reciprocal action, which was the Mid2p induced the phosphorylated Spm1, while the Pmp1 dephosphorylated Spm1, existed among the Spm1、Mid2 and Pmp1 in S.pombe treated with edelfosine. Conclusion The inhibition of edelfosine on cytokinesis and cell growth due to the effect of Spm1、Mid2 and Pmp1.