Project description:Analysis of DDX20 knockdown - hepatocellular carcinoma cells. The expression levels of genes driven by NF-kB and related with carcinogenesis, were significantly enhanced in DDX20-knockdown cells. One condition experiment, HepG2 vs. HepG2-DDX20 knockdown cells
Project description:Analysis of DDX20 knockdown - hepatocellular carcinoma cells. The expression levels of genes driven by NF-kB and related with carcinogenesis, were significantly enhanced in DDX20-knockdown cells.
Project description:MicroRNAs (miRNAs) are small RNAs that regulate the expression of specific target genes. While deregulated miRNA expression levels have been detected in many tumors, whether miRNA functional impairment is also involved in carcinogenesis remains unknown. We investigated whether deregulation of miRNA machinery components and subsequent functional impairment of miRNAs are involved in hepatocarcinogenesis. Among miRNA-containing ribonucleoprotein complex components, reduced expression of DDX20 was frequently observed in human hepatocellular carcinomas, in which enhanced NF-kB activity is closely linked to carcinogenesis. Because DDX20 normally suppresses NF-kB activity by preferentially regulating the function of the NF-kB suppressing miRNA-140, we hypothesized that impairment of miRNA-140 function may be involved in hepatocarcinogenesis. Dnmt1 was identified as a direct target of miRNA-140, and increased Dnmt1 expression in DDX20-deficient cells hypermethylated the promoters of metallothionein genes, resulting in decreased metallothionein expression leading to enhanced NF-kB activity and hepatocarcinogenesis. MiRNA-140 knockout mice were prone to hepatocarcinogenesis and showed phenomena similar to those of DDX20 deficiency, suggesting that miRNA-140 plays a central role in DDX20 deficiency–related pathogenesis. Conclusion: These results indicate that miRNA-140 acts as a liver tumor suppressor, and that impairment of miRNA-140 function due to a deficiency of DDX20, a miRNA machinery component, could lead to hepatocarcinogenesis. Genome wide DNA methylation profiling of control and DDX20-knockdown HepG2 cells. Bisulphite converted DNA from the 2 samples were hybridised to the Illumina HumanMethylation450 BeadChip.
Project description:We have sequenced miRNA libraries from human embryonic, neural and foetal mesenchymal stem cells. We report that the majority of miRNA genes encode mature isomers that vary in size by one or more bases at the 3’ and/or 5’ end of the miRNA. Northern blotting for individual miRNAs showed that the proportions of isomiRs expressed by a single miRNA gene often differ between cell and tissue types. IsomiRs were readily co-immunoprecipitated with Argonaute proteins in vivo and were active in luciferase assays, indicating that they are functional. Bioinformatics analysis predicts substantial differences in targeting between miRNAs with minor 5’ differences and in support of this we report that a 5’ isomiR-9-1 gained the ability to inhibit the expression of DNMT3B and NCAM2 but lost the ability to inhibit CDH1 in vitro. This result was confirmed by the use of isomiR-specific sponges. Our analysis of the miRGator database indicates that a small percentage of human miRNA genes express isomiRs as the dominant transcript in certain cell types and analysis of miRBase shows that 5’ isomiRs have replaced canonical miRNAs many times during evolution. This strongly indicates that isomiRs are of functional importance and have contributed to the evolution of miRNA genes
Project description:RNA-seq on HepG2 cells treated with a CRISPR gRNA against DDX20. (DDX20-BGHcLV10) For data usage terms and conditions, please refer to http://www.genome.gov/27528022 and http://www.genome.gov/Pages/Research/ENCODE/ENCODE_Data_Use_Policy_for_External_Users_03-07-14.pdf