Oligonucleotides Containing Pyrazolo[3,4-d]Pyrimidines: 8-Aza-7-deazaadenines With Bulky Substituents in the 2- or 7-Position

The synthesis of the 2′-deoxyadenosine analogues 1b, 2b, and 3c modified at the 7- and/or 2-position is described. The effect of 7-chloro and 2-methylthio groups on the duplex stability is evaluated. For that, the nucleosides 1b, 2b, and 3c were converted to the corresponding phosphoramidites 15, 19, and 22, which were employed in the solid-phase oligonucleotide synthesis. In oligonucleotide duplexes, compound 1b forms stable base pairs with dT, of which the separated 1b- dT base pairs contribute stronger than that of the consecutive base pairs. Compound 2b shows universal base pairing properties while its N8 isomer 3c forms duplexes with lower stability.     

Synthesis of 3′-Thioribouridine, 3′-Thioribocytidine,and Their Phosphoramidites

Abstract

3′-Thio-3′-deoxyribonucleosides (U and C) have been synthesized via Vorbruggen-type glycosylation with 3-S-benzoyl-5-O-toluoyl-1,2-O-diacetylfuranose, which was obtained from 1,2-O-isopropylidene-5-O-toluoyl-3-O-trifluoromethanesulfonyl-α-D-xylofuranose. 3′-Thio-3′-deoxyuridine has been converted to its phosphoramidite.     

ScFKBP12 bridges rapamycin and AtTOR in Arabidopsis

FKBP12 encodes a prolyl isomerase and highly conserved in eukaryotic species. In yeasts and animals, FKBP12 can interact with rapamycin and FK506 to form rapamycin-FKBP12 and FK506-FKBP12 complex, respectively. In higher plants, FKBP12 protein lost its function to bind rapamycin and FK506. Early studies showed that yeast and human FKBP12 protein can restore the rapamycin sensitivity in Arabidopsis, but the used concentration is 100–1000 folds higher than that in yeast and animals. High concentration of drugs would increase the cost and cause the potential secondary effects on plant growth and development. Here we further discovered that BP12 plants generated in our previous study are hypersensitive to rapamycin at the concentration as low as that is effective in yeast and animals. It is surprising to observe that WT and BP12 plants are not sensitive to FK506 in normal growth condition. These findings advance the current understanding of rapamycin-TOR signaling in plants.     

Role of SKP1-CUL1-F-Box-Protein (SCF) E3 Ubiquitin Ligases in Skin Cancer

Many biological processes such as cell proliferation, differentiation, and cell death depend precisely on the timely synthesis anddegradation of key regulatory proteins. While protein synthesis can be regulated at multiple levels, protein degradation is mainlycontrolled by the ubiquitineproteasome system (UPS), which consists of two distinct steps: (1) ubiquitylation of targeted protein by E1ubiquitin-activating enzyme, E2 ubiquitin-conjugating enzyme and E3 ubiquitin ligase, and (2) subsequent degradation by the 26Sproteasome. Among all E3 ubiquitin ligases, the SCF (SKP1-CUL1-F-box protein) E3 ligases are the largest family and are responsiblefor the turnover of many key regulatory proteins. Aberrant regulation of SCF E3 ligases is associated with various human diseases, such ascancers, including skin cancer. In this review, we provide a comprehensive overview of all currently published data to define a promotingrole of SCF E3 ligases in the development of skin cancer. The future directions in this area of research are also discussed with an ultimategoal to develop small molecule inhibitors of SCF E3 ligases as a novel approach for the treatment of human skin cancer. Furthermore,altered components or substrates of SCF E3 ligases may also be developed as the biomarkers for early diagnosis or predicting prognosis.     

Identifying MicroRNA and mRNA Expression Profiles in Embryonic Stem Cells Derived from Parthenogenetic, Androgenetic and Fertilized Blastocysts

MicroRNAs (miRNAs) are a class of highly conserved small non-coding RNA molecules that play a pivotal role in several cellular functions. In this study, miRNA and messenger RNA (mRNA) profiles were examined by Illumina microarray in mouse embryonic stem cells (ESCs) derived from parthenogenetic, androgenetic, and fertilized blastocysts. The global analysis of miRNA-mRNA target pairs provided insight into the role of miRNAs in gene expression. Results showed that a total of 125 miRNAs and 2394 mRNAs were differentially expressed between androgenetic ESCs (aESCs) and fertilized ESCs (fESCs), a total of 42 miRNAs and 87 mRNAs were differentially expressed between parthenogenetic ESCs (pESCs) and fESCs, and a total of 99 miRNAs and 1788 mRNAs were differentially expressed between aESCs and pESCs. In addition, a total of 575, 5 and 376 miRNA-mRNA target pairs were observed in aESCs vs. fESCs, pESCs vs. fESCs, and aESCs vs. pESCs, respectively. Furthermore, 15 known imprinted genes and 16 putative uniparentally expressed miRNAs with high expression levels were confirmed by both microarray and real-time RT-PCR. Finally, transfection of miRNA inhibitors was performed to validate the regulatory relationship between putative maternally expressed miRNAs and target mRNAs. Inhibition of miR-880 increased the expression of Peg3, Dyrk1b, and Prrg2 mRNA, inhibition of miR-363 increased the expression of Nfat5 and Soat1 mRNA, and inhibition of miR-883b-5p increased Nfat5, Tacstd2, and Ppapdc1 mRNA. These results warrant a functional study to fully understand the underlying regulation of genomic imprinting in early embryo development.     

大豆转录因子GmERF5的克隆、表达及功能分析

ERF转录因子是植物中特有的转录因子家族之一, 在植物响应生物和非生物胁迫过程中发挥重要的调控作用。通过对大豆(Glycine max)吉林32未成熟胚的表达谱分析, 利用RT-PCR技术从大豆中克隆了1个新的ERF转录因子GmERF5。GmERF5具有237个氨基酸残基, 分子量为26.09 kDa, 等电点为6.85, 其开放阅读框长714 bp。该转录因子蛋白与Gh-ERF2蛋白的同源性最高, 它们同属ERF亚家族的第IV亚类。实时荧光定量PCR分析表明, 该蛋白基因在大豆的根中表达量最高, 且受干旱、高盐、低温及乙烯、脱落酸和茉莉酸甲酯的诱导上调表达。亚细胞定位实验结果表明, GmERF5蛋白定位于细胞核中。转录激活能力分析结果显示, GmERF5可以激活报告基因的表达, 为转录激活子。综合以上结果, 认为GmERF5可能作为转录调控因子参与大豆生物和非生物胁迫的应答。     

Systematic study of human long intergenic non-coding RNAs and their impact on cancer

The functional impact of several long intergenic non-coding RNAs (lincRNAs) has been characterized in previous studies. However, it is difficult to identify lincRNAs on a large-scale and to ascertain their functions or predict their structures in laboratory experiments because of the diversity, lack of knowledge and specificity of expression of lincRNAs. Furthermore, although there are a few well-characterized examples of lincRNAs associated with cancers, these are just the tip of the iceberg owing to the complexity of cancer. Here, by combining RNA-Seq data from several kinds of human cell lines with chromatin-state maps and human expressed sequence tags, we successfully identified more than 3000 human lincRNAs, most of which were new ones. Subsequently, we predicted the functions of 105 lincRNAs based on a coding-non-coding gene co-expression network. Finally, we propose a genetic mediator and key regulator model to unveil the subtle relationships between lincRNAs and lung cancer. Twelve lincRNAs may be principal players in lung tumorigenesis. The present study combines large-scale identification and functional prediction of human lincRNAs, and is a pioneering work in characterizing cancer-associated lincRNAs by bioinformatics.     

A novel strategy to inhibit the reproduction and translation of hepatitis C virus

Hepatitis C virus (HCV), a positive single-stranded RNA virus, is a major cause of liver disease in humans. Herein we report a novel strategy to inhibit the reproduction and translation of HCV using a short RNA, named an Additional RNA, to activate the endonuclease activity of Argonaute 2 (Ago2). In the presence of the Additional RNA, the HCV genome RNA has the requisite 12 nucleotides of base-pairing with microRNA-122. This activates the endonuclease activity of Ago2, resulting in cleavage and release of the HCV genome RNA from Ago2 and microRNA-122. The free HCV genome RNA would be susceptible to intracellular degradation, effectively inhibiting its reproduction and translation. This study presents a new method to inhibit HCV that may hold great potential for HCV treatment in the future.     

差异显示法克隆与小麦低温诱导相关的磷脂酰乙醇胺结合蛋白基因

本研究利用差异显示技术检测经低温处理的小麦品种"石新828"及对照材料中的mRNA,获得2条差异片段序列。经Blast比对后,发现其中一条长为293bp的差异片段序列与小麦的一个冷调蛋白基因的mRNA(GenBank:AB097412.1)同源性为99%。该基因编码的蛋白属于磷脂酰乙醇胺结合蛋白家族,命名为wpebp。经荧光定量PCR分析,wpebp基因的表达量随低温处理时间的增长总体呈上升趋势,表明该基因与小麦的抗寒能力相关。