目的 建立并优化检测真核细胞mRNA氧化损伤的方法——反转录阻断-双引物扩增法,检测p53 mRNA氧化损伤.方法 建立非细胞体系和细胞体系mRNA氧化损伤模型,提取RNA并反转录成cDNA,根据所检测mRNA的5’端和3’端各设计一对引物,以cDNA为模板进行实时定量PCR.结果 非细胞体系和细胞体系氧化处理组GAPDH和p53 mRNA的氧化损伤程度均明显高于对照组,且随着过氧化氢浓度增加RNA氧化损伤增强；同时一定限度内降低反转录酶用量能提高检测灵敏度.结论 本研究建立并优化的RNA氧化损伤检测方法能检测特定mRNA对氧化的敏感性及损伤程度,为分析相关疾病造成的RNA氧化损伤以及探索其发病机制和治疗方法提供了技术支持.

An increasing data indicates that altered microRNAs(miRNAs)participate in the radiation-induced DNA damage response.However,a correlation of mRNA and miRNA profiles across the entire genome and in response to irradiation has not been thoroughly assessed.We analyzed miRNA microarray data collected from HeLa cells after ionizing radiation(IR),quantified the expression profiles of mRNAs and performed comparative analysis of the data sets using target prediction algorithms,Gene Ontology(GO)analysis,pathway analysis,and gene network construction.The results showed that the altered miRNAs were involved in regulation of various cellular functions.miRNA-gene network analyses revealed that miR-186,miR-106b,miR-15a/b,CCND1and CDK6 played vital role in the cellular radiation response.Using qRT-PCR,we confirmed that twenty-two miRNAs showed differential expression in HeLa cells treated with IR and some of these miRNAs affected cell cycle progression.This study demonstrated that miRNAs influence gene expression in the entire genome during the cellular radiation response and suggested vital pathways for further research.

Objective To establish a new method of poly(U)-tailed RT-PCR to detect microRNA(miRNA).Methods The total RNA of cells was extracted and polyuridylylated by poly(U) polymerase,then the cDNA was obtained by reverse transcriptase with the universal primer,and the miRNA was detected by real-time quantitative PCR.Results This method of poly(U)-tailed RT-PCR could better detect miRNA with specificity and efficiency.Conclusion This method of poly(U)-tailed RT-PCR for detection of miRNAs is simple,economical and efficient.

microRNAs (miRNAs) are a versatile class of non-coding RNAs involved in regulation of various biological processes. miRNA-122 (miR-122) is specifically and abundantly expressed in human liver. In this study, we employed 3′-end biotinylated synthetic miR-122 to identify its targets based on affinity purification. Quantitative RT-PCR analysis of the affinity purified RNAs demonstrated a specific enrichment of several known miR-122 targets such as CAT-1 (also called SLC7A1), ADAM17 and BCL-w. Using microarray analysis of affinity purified RNAs, we also discovered many candidate target genes of miR-122. Among these candidates, we confirmed that protein kinase, interferon-inducible double-stranded RNA-dependent activator (PRKRA), a Dicer-interacting protein, is a direct target gene of miR-122. miRNA quantitative-RT–PCR results indicated that miR-122 and small interfering RNA against PRKRA may facilitate the accumulation of newly synthesized miRNAs but did not detectably affect endogenous miRNAs levels. Our findings will lead to further understanding of multiple functions of this hepato-specific miRNA. We conclude that miR-122 could repress PRKRA expression and facilitate accumulation of newly synthesized miRNAs.

Cisplatin is a classic chemotherapy agent used for treating human non-small cell lung cancer (NSCLC). However, cisplatin resistance is a challenge against successful clinical use. Glutathione S-transferase P1 (GSTP1) has been reported to contribute to cisplatin resistance in many studies. MicroRNAs (miRNAs) are short non-coding RNAs that are 21–25 nucleotides in length. They play a role in post-transcriptional gene regulation by inducing repression and/or mRNA degradation. Recent studies have shown that miRNAs are responsible for cisplatin resistance. This study aims to determine whether deregulated miRNAs can sensitize human lung adenocarcinoma cells to cisplatin by targeting GSTP1. Real-time RT-PCR revealed that GSTP1 mRNA expression was 2.7±0.38 folds (p=0.039) upregulated in A549/CDDP cells, compared with the parental A549 cells, while miR-513a-3p expression was 0.34±0.03 folds (p=0.023) downregulated. Luciferase activity assay proved that GSTP1 was a target gene of miR-513a-3p, which was confirmed by Western blot analysis. Furthermore, CCK-8 assay showed that overexpression of miR-513a-3p could enhance cisplatin-induced apoptosis in human lung adenocarcinoma cell lines, A549/CDDP and SPC-A-1. In conclusion, our data demonstrated that miR-513a-3p can sensitize human lung adenocarcinoma cells to cisplatin by targeting GSTP1.

Ionizing radiation (IR) causes severe cellular damage both directly and indirectly and disrupts RNA integrity. RNA strand breaks are the most frequent type of damage caused by IR. RNA damage is involved in the development of degenerative diseases, including Alzheimer’s disease and Parkinson’s disease. However, the mechanism of mRNA damage and any resulting pathophysiological outcomes are poorly understood. This is partly because there is a lack of sensitive tools to monitor damage randomly occurring in RNA, especially RNA strand break damage in a given RNA. In this work, a method using the reverse transcription polymerase chain reaction (RT-PCR) after poly(A) addition to 3′-end of RNA to determine RNA strand break damage in a specific RNA by poly(A) polymerase has been developed. The levels of damage in specific mRNAs, including ABL1, TP53, GADD45A and ATR from IR-treated HeLa cells were examined. Strand breaks were detected in all mRNAs examined. The study provides a novel and sensitive method based on 3′-end poly(A)-tailing RT-PCR to monitor RNA strand break damage.

目的探讨microRNA-193b（miR-193b）在HepG2细胞中对K-Ras蛋白表达的调控作用。方法 Tar-getScan软件预测获得miR-193b调控候选靶基因K-ras;构建包含预测miR-193b作用靶位点的K-rasmRNA3′UTR野生型和突变型荧光素酶报告基因载体pGL-KRAS和pGL-Mu-KRAS,检测转染HepG2细胞的荧光素酶活性;合成miR-193b的dsRNA,转染HepG2细胞,实时定量PCR和Western印迹检测对K-rasmRNA和蛋白表达的影响。结果与结论 miR-193b可以与K-rasmRNA3′UTR结合。在HepG2中,miR-193b在mRNA和蛋白水平下调K-ras基因表达。

BACKGROUND AND AIMS:Recently, some miRNAs have been reported to be connected closely with the development of human hepatocellular carcinoma. However, the functions of these miRNAs in HCC remain largely undefined.METHODS:The expression profiles of miR-193b were compared between HCC tissues and adjacent normal liver tissues using qRT-PCR method. This method was also be used to screen the potential target genes of miR-193b. A luciferase reporter assay was conducted to confirm target association. Finally, the functional effect of miR-193b in hepatoma cells was examined further.RESULTS:miR-193b was significantly down-regulated in most of the HCC tissues compared to the matching non-tumoural liver tissues. Furthermore, ectopic expression of miR-193b dramatically suppressed the ability of hepatoma cells to form colonies in vitro and to develop tumours in nude mice. CCND1 and ETS1 were revealed to be regulated by miR-193b directly. By regulating the expressions of these oncogenes, miR-193b induced cell cycle arrest and inhibited the invasion and migration of hepatoma cells.CONCLUSIONS:miR-193b may function as a tumour suppressor in the development of HCC by acting on multiple tumourigenic pathways.

Five compounds were isolated from the MeOH extract of metabolites of Deinococcus radiodurans by silica gel column chromatography and recrystallization.On the basis of spectroscopic data,they were identified as adenine(1),thymine(2),uracil(3),adenosine(4),and L-alanine(5).All compounds were obtained from metabolites of D.radiodurans for the first time.

Background In recent years, some miRNAs have been reported to be connected closely with the development of human hepatocellular carcinoma. In our previous studies, a set of miRNAs were revealed to be dysregulated in HCC tissues. However, the functions of these miRNAs in HCC remain largely undefined. Methods The expression profiles of miR-183 were compared between HCC tissues and adjacent normal liver tissues using qRT-PCR method. This method was used to screen the potential target genes of miR-183. A luciferase reporter assay was conducted to confirm target association. Finally, the functional effect of miR-183 in hepatoma cells was examined. Results Among the 25 HCC samples analyzed, microRNA-183 was significantly up-regulated (twofold to 367-fold) in 17 samples compared with the matching nontumoral liver tissues. Programmed cell death 4 (PDCD4) was identified as the target gene of miR-183. Moreover, PDCD4 is a proapoptotic molecule involved in TGF-β1-induced apoptosis in human HCC cells, we found that miR-183 transfectants were resistant to apoptosis induced by TGF-β1. Conclusions We conclude that miR-183 can inhibit apoptosis in human HCC cells by repressing the PDCD4 expression, and miR-183 may play an important role in HCC development.

MicroRNAs (miRNAs) are a class of small regulatory RNAs that are thought to be involved in diverse biological processes by regulating gene expression. Numerous miRNAs have been identified in various species, and many more miRNAs remain to be detected. Generally, hundreds of mRNAs have been predicted to be potential targets of one miRNA, so it is a great challenge to identify the genuine miRNA targets. Here, we generated the cell lines depleted of Drosha protein and screened dozens of transcripts (including Cyclin D1) regulated potentially by miRNA-mediated RNA silencing pathway. On the basis of miRNA expressing library, we established a miRNA targets reverse screening method by using luciferase reporter assay. By this method, we found that the expression of Cyclin D1 (CCND1) was regulated by miR-16 family directly, and miR-16 induced G1 arrest in A549 cells partially by CCND1. Furthermore, several other cell cycle genes were revealed to be regulated by miR-16 family, including Cyclin D3 (CCND3), Cyclin E1 (CCNE1) and CDK6. Taken together, our data suggests that miR-16 family triggers an accumulation of cells in G0/G1 by silencing multiple cell cycle genes simultaneously, rather than the individual target.

Member strains of the genus Deinococcus exhibit a remarkable capacity to resist the lethal effects of ionization radiation to other bacteria.So far validly named 23 strains have been reported,and the applications of them have attracted much attention.Taxonomy and application of the genus is summarized in this paper.

miRNAs regulate gene expression by inhibiting translation or by targeting messenger RNA (mRNA) for degradation in a post-transcriptional fashion. In the present study, we show that ectopic expression of miR-34a reduces both mRNA and protein levels of cyclin D1 (CCND1) and cyclin-dependent kinase 6 (CDK6). We also demonstrate that miR-34a targets the 3'-untranslated mRNA region of CCND1 as well as CDK6, which in turn interferes with phosphorylation of retinoblastoma. In addition, we show that overexpression of miR-34a induces a significant G1 cell-cycle arrest in the A549 cell line. Taken together, our data suggest that the effects of miR-34a on G1 cell cycle arrest are through the down-regulation of CCND1 and CDK6, which is associated with other targets of miR-34a either additively or synergistically.

目的:利用AdEasy系统构建miR-195的腺病毒表达载体,为研究miR-195的功能提供条件.方法:将miRNA-195前体序列从已构建的pcDNA-miR-195载体中克隆进穿梭载体pAdTrack-CMV,通过与骨架载体pAdEasy-1在大肠杆菌BJ5183中高效同源重组,获得完整的重组腺病毒质粒.利用HEK293细胞包装并扩增重组腺病毒Ad-195.Ad-195感染肺癌细胞A549后,利用miRNA的定量RT-PCR技术检测Ad-195在细胞中表达miR-195情况.随后荧光素酶报告基因实验证明,Ad-195表达的miR-195能够作用于BCL2基因上预测的miR-195靶位点.结果:实时定量PCR检测显示,Ad-195感染肺癌细胞A549后,miR-195表达水平有显著的上调.结论:miR-195的腺病毒表达载体构建成功,能够用于在细胞内过表达具有生物学功能的miR-195.

tRNAs play a central role in protein translation, acting as the carrier of amino acids. By cloning microRNAs, we unexpectedly obtained some tRNA fragments generated by tRNA cleavage in the anticodon loop. These tRNA fragments are present in many cell lines and different mouse tissues. In addition, various stress conditions can induce this tRNA cleavage event in mammalian cells. More importantly, angiogenin (ANG), a member of RNase A superfamily, appears to be the nuclease which cleaves tRNAs into tRNA halves in vitro and in vivo. These results imply that angiogenin plays an important physiological role in cell stress response, except for the known function of inducing angiogenesis.

The initiation and progression of tumor is regulated by multiple genes. Survivin belongs to the inhibitor of apoptosis protein (IAP) family and is overexpressed in most types of human tumors. Apoptin, originally identified from chicken anemia virus (CAV), can specifically induce apoptosis of human tumor cells rather than normal cells. In this study, survivin expression was silenced by microRNA (miRNA)-mediated RNA interference (RNAi); meanwhile, the engineered miRNA vector was also designed to express apoptin gene. The apoptosis and cell growth were then examined by flow cytometry and MTT assay. The miRNA-mediated knockdown of survivin in combination with apoptin overexpression significantly induced apoptosis and inhibited cell growth. Importantly, the combined strategy was more effective on inducing apoptosis and inhibiting cell growth than either survivin downregulation or apoptin overexpression alone. Taken together, the combined strategy offers potential advantages in control of tumorigenesis, and thus deserves further research as a preferred approach in cancer gene therapy

目的:膜研究膜型-1基质金属蛋白酶（MT1- MMP）反义RNA对人胃癌细胞BGC823靶基因表达和侵袭特性的影响方法:利用基因重组技术构建人MT1-MMP反义RNA真核表达载体,转染人胃癌细胞BGC823,应用RT-PCR、MTT、明胶酶谱和体外侵袭实验等方法观察人胃癌细胞BGC823转染前后,MT1-MMP mRNA表达水平、细胞生长、明教酶A活性及细胞体外侵袭能力等指标的变化.结果:成功构建了MT1-MMP反义RNA真核表达载体pasMMP14,将其转染胃癌细胞BGC823后,与阴性对照组相比,实验组MT1- MMP mRNA表达水平降低,抑制率为36%.转染48 h,明教酶A的活化受到了明显抑制.转染72 h,细胞增殖明显受抑（t=2.358,P＜0.01 vs空白组:t=2.727 P＜0.01 vs阴性组）.实验组的穿膜细胞数明显低于空白对照组和阴性对照组（t=5.744,P＜0.01;t=5.695,P＜0.01）.结论:反义RNA对人胃癌细胞MT1-MMP基因表达和侵袭能力具有明显的抑制作用,MT1-MMP基因可作为胃癌抗侵袭治疗的分子靶点.

Objective:To produce and identify monoclonal antibodies against clenbuterol(CL).Methods:CL-conjugated antigens(BSA-CL and OVA-CL) were produced by coupling diazotized CL with bovine serum albumin(BSA) and ovalbumin(OVA),respectively.Hybridoma cell lines were established for specificity to CL by using the conventional hybridoma technique.Results and Conclusion: Eighteen hybridoma cell lines were established.The ELISA titer of hybridoma supernatants of three clones in the 18 lines were 1∶1 280 in E9-C11,1∶1 000 in C11-E3,and 1∶800 in E7-G8.The ascites titers of all three clones were 1×10-6.The affinity constant was 2.4×10-8mol/L,2.83×10-8 mol/L,and 3.28×10-8 mol/L,respectively,and all three McAb belonged to IgG1 subclass.McAb of E9-C11 indicated high sensitivity with an IC50 of 6.1035 μg/L to CL,higher than 781.25 μg/L to salbuterol,and showed lower than 0.78% cross activity towards salbuterol,no cross reactivity towards epinephrine, norepinephrine,isoprenaline,leukodopamine,antibiotics and vitamin.Furthermore,protein blotting assay showed that these McAb had high specificity to CL and can be used to detect CL residues.

The microRNAs (miRNAs) are a kind of single strand small noncoding RNAs (approximately 22nt) with probable roles in the silencing gene expressions. To date, a large number of miRNAs have been identified in several organisms, but the function of the vast majority of these molecules remains to be determined. To study their functions, a library of vectors expressing miRNAs, including more than 170 kinds of human miRNAs were developed. The ability of some miRNA vectors to express miRNAs was validated with Northern blot and dual luciferase assays. The results indicated that these vectors could express pre-miRNAs and mature miRNAs in HEK-293 cells. Furthermore, they could suppress the expression of luciferase tagged with a sequence complementary to corresponding miRNAs. All these data show that these miRNA expression vectors can drive functional miRNA expression, and they can be used to screen functional miRNAs.

Objective:To construct a random RNAi library by using a RNAi expression vector with convergent U6 and H1 promoters.Methods:Firstly,RNAi plasmids targeting EGFP gene and p53 gene were constructed respectively based on pRHU vector in order to determine the efficiency of the vector and assayed their interfering effects at cellular level.Secondly,a DNA template containing random sequence and two linkers suited for PCR amplification was designed and synthesized.After PCR amplification and HindⅢ/ BamHⅠ digestion,the DNA fragment was cloned into pRHU vector and transformed into high efficient competent cells.Twenty clones were randomly selected and sequenced.Results:pRHU Vector was determined to be an efficient RNAi expression vector based on the fact that it could interfere expressions of exogenous EGFP gene and endogenous p53 gene.A random RNAi library with the capacity of 4×106 clones derived from 50 μg of initial pRHU vector was constructed in a relatively short cycle.DNA Sequencing results showed that all the twenty randomly selected clones contained GN17-19 sequence and their sequences were not identical one another.Conclusion:A simple and rapid method for constructing a random RNAi library based on RNAi expression vector with convergent U6 and H1 promoters was established and laid foundation for further genomic screening of functional genes.