MicroRNAs in human virus genomes: helping hands for viral infection.

MicroRNAs (miRNAs) are small noncoding regulatory RNAs that control essential cellular activities. Many viruses use these regulators to help infect host cells and maintain their presence in those cells. Therefore, virus-encoded miRNAs are important tools for viruses in the battle with their hosts.

Overexpression of hnRNPC2 induces multinucleation by repression of Aurora B in hepatocellular carcinoma cells.

Heterogeneous ribonuclear protein C2 (hnRNPC2), an RNA binding protein, is a component of hnRNPC which is upregulated in many tumors. Multinucleation exists in many tumors and is positively correlated with tumor grade. To uncover the correlation between hnRNPC2 and multi-nucleation in hepatocellular carcinoma SMMC-7721 cells, we constructed a pEGFP-hnRNPC2 vector and transfected it into cancer cells.

Cancer cell growth suppression by a 62nt AU-rich RNA from C/EBPβ 3'UTR through competitive binding with HuR.

AU-rich elements are functional motifs in the 3'untranslated region of mRNA and are binding sites for the RNA binding protein HuR, an mRNA stabilizer and translation enhancer implicated in carcinogenesis. It is not clear whether, and, if so, how the AU-rich elements function in cells when they are separated from their mRNA and form an independent RNA species. Here, we show that a short RNA with AU-rich elements derived from C/EBPβ 3'UTR suppressed growth in a human liver cancer cell line.

Tumor suppression by RNA from C/EBPβ 3'UTR through the inhibition of protein kinase Cε activity.

Background: Since the end of last century, RNAs from the 3'untranslated region (3'UTR) of several eukaryotic mRNAs have been found to exert tumor suppression activity when introduced into malignant cells independent of their whole mRNAs. In this study, we sought to determine the molecular mechanism of the tumor suppression activity of a short RNA from 3'UTR of C/EBPβ mRΝΑ (C/EBPβ 3'UTR RNA) in human hepatocarcinoma cells SMMC-7721.

Methodology/principal Findings: By using Western blotting, immunocytochemistry, molecular beacon, confocal microscopy, protein kinase inhibitors and in vitro kinase assays, we found that, in the C/EBPβ 3'UTR-transfectant cells of SMMC-7721, the overexpressed C/EBPβ 3'UTR RNA induced reorganization of keratin 18 by binding to this keratin; that the C/EBPβ 3'UTR RNA also reduced phosphorylation and expression of keratin 18; and that the enzyme responsible for phosphorylating keratin 18 is protein kinase Cε.

C/EBPbeta sustains undifferentiated state of murine embryonic stem cells as a mediator of LIF.

C/EBPbeta (also called NF-IL6) is a multifunctional transcription factor, a major function of which is the enhancement of cellular differentiation. Leukemia inhibitory factor (LIF) is a cytokine playing divergent roles in different cell types: induces differentiation in preadipocytes and, however, inhibits differentiation in pluripotent murine embryonic stem (mES) cells. However, roles of C/EBPbeta in mES cells are obscure.

Systemic delivery of full-length C/EBP beta/liposome complex suppresses growth of human colon cancer in nude mice.

C/EBP beta (CCAAT/enhancer-binding protein beta) is an important transcription factor involved in cellular proliferation and differentiation. Overexpression of the full-length C/EBP beta protein results in cellular growth arrest and apoptosis. Using a nonviral liposome as carrier, we delivered the full-length C/EBP beta expression plasmid, pCN, into nude mice bearing CW-2 human colon cancer tumors via tail vein.

Direct isolation of specific RNA-interacting proteins using a novel affinity medium.

Isolation of proteins that specifically interact with a given RNA or RNA regulation element is essential for studies on the molecular mechanisms of gene expression. Here, a novel method for direct isolation of such interacting proteins is described. It uses an affinity medium that consists of an interacting RNA with an artificially added 'tail', which is annealed to one end of a DNA 'arm', the other end of which is fixed covalently on the surface of aminosilanized glass powder.

Proteomic analysis of differential protein expression in a human hepatoma revertant cell line by using an improved two-dimensional electrophoresis procedure combined with matrix assisted laser desorption/ionization-time of flight-mass spectrometry.

The proteomic profiles of a human hepatoma revertant, CL1, and its original cell line, SMMC7721, were compared by using an improved two-dimensional electrophoresis (2-DE) procedure, with multi-IPGstrips gels (length View Article and Find Full Text PDF

Gene expression profile favoring phenotypic reversion: a clue for mechanism of tumor suppression by NF-IL6 3'UTR.

Transfection of cDNA in 3'untranslated region of human nuclear factor for interleukin-6 (NF-IL6 3'UTR) induced tumor suppression in a human hepatoma cell line. cDNA array analysis was used to reveal changes in gene expression profile leading to tumor suppression The results indicate that this suppression was not due to activation of dsRNA-dependent protein kinase, nor to inactivation of oncogenes; rather, all the changes in expression of known genes, induced by NF-IL6 3'UTR cDNA may be ascribed to the suppression of cellular malignancy. Therefore, our results imply that this 3'untranslated region may have played role of a regulator of gene expression profile.

Multi-strips on one gel method to improve the reproducibility, resolution power and high-throughput of two-dimensional electrophoresis.

Two-dimensional polyacrylamide gel electrophoresis is one of the most key separation tools which can reveal hundreds or even thousands of proteins at a time in proteomic research. In this paper, we report a new IPG strip application, called multi-strips on one gel (MSOG) method. By comparing the 2-DE patterns of the same sample, the different state samples and the same sample in the different second dimensional SDS running systems (large size and medium size gels), we found this new method can not only improve the reproducibility and resolution power of 2-DE pattern, but also achieve high throughput and economical format which is helpful to automatic proteomic research.

An NF-IL6 3'UTR RNA-specific Binding Protein in E. coli Purification and Partial Protein Sequencing.

protein was found in E.coli which can specifically bind to NF-IL6 mRNA 3'UTR. After a series of purification steps, the RNA-specific binding protein was directly sequenced on the Porton LF3200 Protein Sequencer.

Enhancement of Macrophage Cytotoxicity by Overexpression of Exogenous NF-IL6 Gene.

NF-IL6 (Nuclear factor for IL-6 expression) is involved in inflammatory reaction, expression of acute-phase proteins and cytokines, apoptosis and suppression of tumor cells, and maintenance of macrophage immunological functions. To investigate the role of highly expressed exogenous NF-IL6 in macrophage tumor cytotoxicity, a recombinant expression plasmid, pCN, which harbored the coding region of NF-IL6, was transfected into murine primary cultured peritoneal resident macrophages by an improved DEAE-dextran method. Western blot showed the high expression of NF-IL6 in these macrophages.

On the Molecular Mechanism of the Tumor Suppressor Function of cDNA Clone p14-6.

Interactions between the RNA transcript of the tumor suppressor cDNA clone, p14-6 (the 3'untranslated region of the nuclear factor for human interleukin-6; NF-IL6 3'UTR), and the reversion-related proteins BNF, were investigated. It was found that: (1) the recognition site of the RNA for BNFs was a 24-nucleotide segment located within the 3'-proximal U-rich sequence; (2) the BNFs were a group of proteins which may interact with each other before interacting with a site on the RNA as a protein complex; (3) possibly only one protein in the complex, namelyR62, directly bound to the RNA site.