Priliminary analysis of microRNA expression profiles of side population cells in human colon cancer cell lines

AIM：To investigate the role of side population (SP) cells in multidrug resistance of colon cancer cells and microRNA biomarkers of SP cells in colon cancer cells. METHODS：SP cells in colon cancer cells were sorted by flow cytometry. The cell viability was measured by MTT method. MicroRNA expression profiles were detected by microRNA chip. MicroRNA expression was verified by real-time PCR. RESULTS：The ratios of SP cells in HCT-15, HT-29 and LoVo colon cancer cell lines were 16.75%, 13.02% and 9.52%, respectively. In all 3 colon cancer cell lines, IC50 of the antitumor drugs including 5-fluorouracil, oxaliplatin and adriamycin for the SP cells were significantly higher than those for non-SP cells (P<005). MicroRNA profiling showed that miR-5000-3p, miR-5009-3p and miR-552 were all up-regulated in the SP cells of all 3 colon cancer cell lines. This result was verified by real-time PCR. CONCLUSION：miR-5000-3p, miR-5009-3p and miR-552 are all up-regulated in the SP cells of colon cancer cell lines, and may be the potential microRNA biomarkers of SP cells in colon cancer.     

草莓基因工程研究进展

综述了近20年来国内外在草莓抗病虫、耐盐碱、抗冻、品质特性、耐贮运性、抗除草剂基因工程的研究概况与进展,对当前草莓基因工程育种工作中存在的问题进行了探讨,对其发展前景进行了展望,指出了多基因转化和利用转录因子、小RNA等调控基因进行转化这2个发展方向并提出了把草莓作为果树基因组学研究的模式植物之一的观点。决定草莓品质(风味、香气和颜色)的物质多是萜类和黄酮类次生代谢物质,这说明今后我国开展草莓次生代谢基因工程对其品质改良的重要性。     

MicroRNA对皮肤毛囊发育调控的研究进展

miRNA是一类由19～25个核苷酸组成的内源性非编码单链小分子RNA,通过与靶基因mRNA3’端非编码区配对结合,降解靶mRNA或阻碍其翻译,进而调节靶基因的表达。文章综述了miRNA的生源说及功能、miRNA在皮肤毛囊中的表达检测以及miRNA对皮肤毛囊发育的调控。     

MicroRNA‐based molecular markers: a novel PCR‐based genotyping technique in Brassica species

DNA‐based molecular markers play a significant role in gene mapping, genetic diversity analysis, germplasm evaluation and molecular marker‐assisted selection. A combination of desirable marker characteristics such as abundant polymorphism, good stability, ease of production and high efficiency is difficult to achieve when utilizing traditional molecular marker systems. MicroRNAs are a type of endogenous non‐coding RNAs prevalent in the genomes of many organisms. The high conservation of miRNA and pre‐miRNA sequences provides an opportunity to develop a novel molecular marker type. We downloaded 82 miRNA sequences from the Brassica miRBase database and designed 46 single miRNA‐based primers which could be randomly combined to generate primer pairs. A proportion of these primer pairs were validated for transferability and polymorphism using DNA from 16 varieties of six Brassica species. The percentage of polymorphic primer pairs were 28.1%, and the average polymorphism information content (PIC) value for the 34 primer pairs was 0.43. Good transferability was verified across species. These results indicate that miRNA‐based markers provide a novel genotyping technique with low costs, high efficiency, stability and good transferability.     

MicroRNA在高等植物逆境响应中的作用机制研究进展

microRNA（miRNA）是一类20~24bp的内源性小分子非编码RNA,广泛存在于真核生物中。成熟的miRNA通过与靶基因较保守的互补位点配对结合,在转录后水平负调控靶基因的表达,参与植物的生长发育、信号转导和逆境响应等过程。本文综述了植物在生物胁迫和非生物胁迫（重金属、干旱、低温、盐、热）响应中miRNA的作用及其调节机理研究进展,指出存在问题并进行展望。     

Preliminary study on miRNA expression spectrum related to chemotherapy resistance in colon cancer

AIM: To screen the chemotherapy resistance-related microRNAs (miRNAs) of colon cancer using gene chip technique, and to explore the mechanism of miRNAs regulating chemotherapy resistance. METHODS: Gene chip technique was used to analyze the expression of miRNAs in colon cancer cell line HCT8 and vincristine-resistant cell line HCT8/v, and screen the miRNAs with significantly different expression. The results were verified by RT-qPCR. The target genes of these miRNAs were predicted, and the Gene Ontology (GO) analysis and the signaling pathway analysis of the predicted genes were carried out. RESULTS: Altogether 342 miRNAs with significantly differential expression were selected, in which 190 were up-regulated, and 152 were down-regulated. The verification results of RT-qPCR showed that the expression of miR-125-5p, miR-181c-5p and miR-153-3 was consistent with the results of chip detection. The expression of miR-130a-3p and miR-149-3p was not consistent with the results of chip detection. The results of GO analysis showed that the main pathway of chemotherapy resistance-related genes was RNA polymerase II regulatory region sequence-specific DNA binding. The chemotherapy resistance-related genes played roles mainly through positive regulation and are mainly located in intracellular membrane-bound organelles. The results of KEGG analysis showed that the pathways associated with the most enriched chemotherapy resistance-related genes were axon guidance pathway, insulin signaling pathway, and phospholipase D signaling pathway.CONCLUSION: miRNAs are closely related to chemotherapy resistance in colon cancer. Through the researches on miRNAs, we can have a deeper understanding of the mechanism of chemotherapy resistance and provide new ideas for reversing chemotherapy resistance in colon cancer.     

水稻microRNA1876功能验证与生物信息学分析

MicroRNA (miRNA)是一类由内源基因组转录的有基因调控功能的非编码短序列RNA,在动植物中参与转录后基因表达调控。为了研究Osa-miRNA1876基因功能,本研究对Osa-miRNA1876进行生物信息学分析,分析出启动子区间有与逆境相关的主要顺式作用元件ARE、GC-motif、GT1-motif、Sp1和LTR,并预测到了靶基因Os02t0476700-01。通过茎环法q RT-PCR,以水稻U6基因为内参基因,对Osa-miRNA1876在水稻分蘖期进行了相对定量。在水稻基因组中,克隆得到Osa-miRNA1876的前体基因,并根据Osa-miRNA1876序列设计了短串联靶标模拟物(short tandem target mimic, STTM)功能片段;将二者整合到植物表达载体pCAMIBA1390,分别获得了过表达载体pOsa-miRNA1876-OE和干扰载体pOsa-miRNA1876-STTM。用于后续的Osa-miRNA1876基因功能研究。