共查询到20条相似文献,搜索用时 15 毫秒
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目的:检测mi R-106b-93-25基因簇对子宫内膜癌细胞增殖及凋亡的影响,并探讨其机制。方法:q RT-PCR检测临床子宫内膜癌标本及癌旁正常组织中mi R-106b、mi R-93和mi R-25及其宿主基因MCM7的表达情况。将micro RNA及其拮抗剂转染ECC-1细胞后,MTT实验检测ECC-1细胞增殖情况,流式细胞术检测ECC-1细胞周期及细胞凋亡情况。荧光素酶报告系统验证mi R-106b和mi R-25分别直接调控p21和Bim。结果:临床标本子宫内膜癌组织与癌旁正常组织相比mi R-106b-93-25簇及其宿主基因MCM7的表达明显增高。mi R-106b-93-25簇能够促进ECC-1细胞增殖,减少凋亡。转染mi R-106b和mi R-93的细胞出现明显的S期阻滞,过表达mi R-25的细胞凋亡明显减少。mi R-106b-93-25簇通过抑制靶基因p21和Bim的表达,引起促增殖、抗凋亡作用。结论:mi R-106b-93-25簇能够促进子宫内膜癌细胞增殖,抑制凋亡,并使细胞发生S期阻滞。mi R-106b-93-25簇在子宫内膜癌的发生与发展中具有重要的作用。 相似文献
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Two miRNA clusters, Mir-17-92 (Mirc1) and Mir-106b-25 (Mirc3), are involved in the regulation of spermatogonial differentiation in mice 总被引:1,自引:0,他引:1
Increasing evidence indicates that microRNAs (miRNAs) may be critical players in spermatogenesis. The miRNA expression profiles of THY1(+)-enriched undifferentiated spermatogonia were characterized, and members of Mir-17-92 (Mirc1) and its paralog Mir-106b-25 (Mirc3) clusters are significantly downregulated during retinoic acid-induced spermatogonial differentiation, both in vitro and in vivo. The repression of microRNA clusters Mir-17-92 (Mirc1) and Mir-106b-25 (Mirc3) by retinoic acid in turn potentially upregulates the expression of Bim, Kit, Socs3, and Stat3. The male germ cell-specific Mir-17-92 (Mirc1) knockout mice exhibit small testes, a lower number of epididymal sperm, and mild defect in spermatogenesis. Absence of Mir-17-92 (Mirc1) in male germ cells dramatically increases expression of Mir-106b-25 (Mirc3) cluster miRNAs in the germ cells. These results suggest that Mir-17-92 (Mirc1) cluster and Mir-106b-25 (Mirc3) cluster miRNAs possibly functionally cooperate in regulating spermatogonial development. 相似文献
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Background
Micro (mi)RNAs are important regulators of plant development. Across plant lineages, Dicer-like 1 (DCL1) proteins process long ds-like structures to produce micro (mi) RNA duplexes in a stepwise manner. These miRNAs are incorporated into Argonaute (AGO) proteins and influence expression of RNAs that have sequence complementarity with miRNAs. Expression levels of AGOs are greatly regulated by plants in order to minimize unwarranted perturbations using miRNAs to target mRNAs coding for AGOs. AGOs may also have high promoter specificity-sometimes expression of AGO can be limited to just a few cells in a plant. Viral pathogens utilize various means to counter antiviral roles of AGOs including hijacking the host encoded miRNAs to target AGOs. Two host encoded miRNAs namely miR168 and miR403 that target AGOs have been described in the model plant Arabidopsis and such a mechanism is thought to be well conserved across plants because AGO sequences are well conserved.Results
We show that the interaction between AGO mRNAs and miRNAs is species-specific due to the diversity in sequences of two miRNAs that target AGOs, sequence diversity among corresponding target regions in AGO mRNAs and variable expression levels of these miRNAs among vascular plants. We used miRNA sequences from 68 plant species representing 31 plant families for this analysis. Sequences of miR168 and miR403 are not conserved among plant lineages, but surprisingly they differ drastically in their sequence diversity and expression levels even among closely related plants. Variation in miR168 expression among plants correlates well with secondary structures/length of loop sequences of their precursors.Conclusions
Our data indicates a complex AGO targeting interaction among plant lineages due to miRNA sequence diversity and sequences of miRNA targeting regions among AGO mRNAs, thus leading to the assumption that the perturbations by viruses that use host miRNAs to target antiviral AGOs can only be species-specific. We also show that rapid evolution and likely loss of expression of miR168 isoforms in tobacco is related to the insertion of MITE-like transposons between miRNA and miRNA* sequences, a possible mechanism showing how miRNAs are lost in few plant lineages even though other close relatives have abundantly expressing miRNAs.Electronic supplementary material
The online version of this article (doi:10.1186/1471-2164-15-1049) contains supplementary material, which is available to authorized users. 相似文献12.
Nan Lin Angela Davis Scott Bahr Trissa Borgschulte Katherine Achtien Kevin Kayser 《Biotechnology progress》2011,27(4):1163-1171
MicroRNAs (miRNAs) play important roles in global gene regulation. Researchers in recombinant protein production have proposed miRNAs as biomarkers and cell engineering targets. However, miRNA expression remains understudied in Chinese Hamster Ovary cells, one of the most commonly used host cell systems for therapeutic protein production. To profile highly conserved miRNA expression, we used the miRCURY? miRNA array for screening miRNAs in CHO cells. The selection criteria for further miRNA profiling included positive hybridization signals and experimentally validated predicted regulatory targets. On the basis of screening, we selected 16 miRNAs for quantitative RT‐PCR profiling. We profiled miR expression in parental CHO DG44 and CHO K1 cell lines as well as four recombinant DG44‐derived CHO lines producing a recombinant human IgG. We observed that miR‐221 and miR‐222 were significantly downregulated in all IgG‐producing cell lines when compared with parental DG44, whereas miR‐125b was significantly downregulated in one IgG‐producing line. In another IgG‐producing line, miR‐19a was significantly upregulated. miRNA expression was also profiled in two of these lines that were amplified by stepwise increase of methotrexate. In both amplified cell lines, let‐7b and miR‐221 were significantly downregulated. In parental CHO K1, let‐7b, miR‐15b, and miR‐17 were significantly downregulated when compared with DG44. The results reported here are the first steps toward profiling highly conserved miRNAs and studying the clonal difference in miRNA expression in CHO cells and may shed light on using miRNAs in cell engineering. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011 相似文献
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Apple miRNAs and tasiRNAs with novel regulatory networks 总被引:2,自引:0,他引:2
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Approximately half of known human miRNAs are located in the introns of protein coding genes. Some of these intronic miRNAs are only expressed when their host gene is and, as such, their steady state expression levels are highly correlated with those of the host gene's mRNA. Recently host gene expression levels have been used to predict the targets of intronic miRNAs by identifying other mRNAs that they have consistent negative correlation with. This is a potentially powerful approach because it allows a large number of expression profiling studies to be used but needs refinement because mRNAs can be targeted by multiple miRNAs and not all intronic miRNAs are co-expressed with their host genes.Here we introduce InMiR, a new computational method that uses a linear-Gaussian model to predict the targets of intronic miRNAs based on the expression profiles of their host genes across a large number of datasets. Our method recovers nearly twice as many true positives at the same fixed false positive rate as a comparable method that only considers correlations. Through an analysis of 140 Affymetrix datasets from Gene Expression Omnibus, we build a network of 19,926 interactions among 57 intronic miRNAs and 3,864 targets. InMiR can also predict which host genes have expression profiles that are good surrogates for those of their intronic miRNAs. Host genes that InMiR predicts are bad surrogates contain significantly more miRNA target sites in their 3' UTRs and are significantly more likely to have predicted Pol II and Pol III promoters in their introns.We provide a dataset of 1,935 predicted mRNA targets for 22 intronic miRNAs. These prediction are supported both by sequence features and expression. By combining our results with previous reports, we distinguish three classes of intronic miRNAs: Those that are tightly regulated with their host gene; those that are likely to be expressed from the same promoter but whose host gene is highly regulated by miRNAs; and those likely to have independent promoters. 相似文献
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