RNA interference (RNAi) is a gene-silencing technology by which small double-stranded RNAs are used to target the degradation of RNA with complementary sequence. RNAi is found in a wide variety of organisms (Caenorhabditis elegans, insects, plants, microorganisms and animals). With RNAi, we have harnessed the gene function to be explored, revolutionized our ability to perform large-scale genetic screens, and even therapeutic potential.
Biology* ; Insects ; RNA ; RNA Interference ; RNA, Double-Stranded

Cardiovascular Diseases ; diagnosis ; therapy ; Humans ; RNA Interference

Growing numbers of studies employ cell line-based systematic short interfering RNA (siRNA) screens to study gene functions and to identify drug targets. As multiple sources of variations that are unique to siRNA screens exist, there is a growing demand for a computational tool that generates normalized values and standardized scores. However, only a few tools have been available so far with limited usability. Here, we present siMacro, a fast and easy-to-use Microsoft Office Excel-based tool with a graphic user interface, designed to process single-condition or two-condition synthetic screen datasets. siMacro normalizes position and batch effects, censors outlier samples, and calculates Z-scores and robust Z-scores, with a spreadsheet output of >120,000 samples in under 1 minute.
High-Throughput Screening Assays ; RNA Interference ; RNA, Small Interfering

RNA interference (RNAi), a highly conserved evolutionary process of post-transcriptional gene silencing, can be triggered by small interfering RNAs (siRNAs) that mediate sequence-specific mRNA degradation. The article summarized some aspects of the mechanism of RNAi, siRNA design and delivery of siRNAs to mammalian somatic cells. And some hurdles in practice were also discussed.
Animals ; Humans ; RNA Interference ; RNA, Small Interfering ; genetics ; Transfection

RNA interference (RNAi) is the sequence-specific gene silencing induced by double-stranded RNA (dsRNA). Being a highly specific and efficient knockdown technique, RNAi not only provides a powerful tool for functional genomics but also holds a promise for gene therapy. The key player in RNAi is small RNA (~22-nt) termed siRNA. Small RNAs are involved not only in RNAi but also in basic cellular processes, such as developmental control and heterochromatin formation. The interesting biology as well as the remarkable technical value has been drawing widespread attention to this exciting new field.
Animals ; Gene Therapy/*methods/trends ; *Genomics ; Human ; *RNA Interference

BACKGROUND: There are no established reports about the expression of the Piwil gene, a subfamily of the Piwi gene involved in RNA silencing and self-renewal, in colorectal carcinomas. It is known that the degree of PIWIL2 expression is higher in colorectal carcinomas. But its clinicopathologic significance remains undetermined. This study reassessed the relationship between PIWIL2 expression and the clinicopathologic parameters in colorectal carcinomas. METHODS: An immunohistochemistry of PIWIL2 expression was done in 60 cases of colorectal carcinoma. This was followed by an analysis of the correlation between PIWIL2 expression and clinicopathologic features and a survival analysis. RESULTS: There were 44 cases (73.3%) where the degree of PIWIL2 expression was relatively higher. The high degree of PIWIL2 expression was significantly correlated with the lower degree of differentiation (p=0.039), deep invasion (p=0.019) and perineural invasion (p=0.027). The overall survival was longer in patients with the lower degree of PIWIL2 expression than in those with the higher degree of PIWIL2 expression. CONCLUSIONS: Our results showed that the degree of PIWIL2 expression was relatively higher in colorectal carcinomas and it was significantly correlated with variable clinicopathologic indicators for a poor prognosis. This indicates that PIWIL2-positive cells contribute to the progression of colorectal cancer.
Colorectal Neoplasms ; Genes, vif ; Humans ; Immunohistochemistry ; Prognosis ; RNA Interference

This study cloned the transcription factor gene PnbHLH which held an open reading frame of 966 bp encoding 321 amino acids. This study constructed the overexpression vector of transcription factor PnbHLH of Panax notoginseng. The combination of PnbHLH overexpression and RNAi of the key enzyme gene PnCAS involved in the phytosterol biosynthesis was achieved in P. notoginseng cells, thus exploring the biosynthetic regulation of P. notoginseng saponins(PNS) by the synergistic effect of PnbHLH overexpression and PnCAS RNAi. The results showed that the PnbHLH transcription factor interacted with the promoters of key enzyme genes PnDS, PnSS and PnSE in the biosynthetic pathway of PNS, and then regulated the expression levels of key enzyme genes and affected the biosynthesis of saponins indirectly. Further study indicated that the synergistic effect of PnbHLH overexpression and PnCAS RNAi was a more effective approach to regulate the biosynthesis of saponins. Compared with the wild type and PnCAS RNAi cells of P. notoginseng, the contents of total saponins and monomeric saponins(Rd, Rb_1, Re, Rg_1 and R_1) were increased to some extent in the cell lines of PnbHLH overexpression and PnCAS RNAi. This indicated that the two ways of forward regulation and reverse regulation of saponin biosynthesis showed superposition effect. This study explored a more rational and efficient regulation strategy of PNS biosynthesis based on the advantages of multi-point regulation of transcription factors as well as the down-regulation of by-product synthesis of saponins.
Intramolecular Transferases ; Panax notoginseng ; RNA Interference ; Saponins ; Transcription Factors/genetics*

This paper reviews the latest development of RNA interference(RNAi). RNA interference is the process of sequence-specific degradation of homologous mRNA triggered by double-stranded RNA. As a technically simple and an effective genetic tool which can exert effect on the expression of gene and substitute for gene knock-out technique in some degree, RNAi phenomena have been broadly validated in diverse model organisms such as Caenorhabditis elegans, Drosophila melanogaster, Arabidopsis thaliana and Neurospora crassa. Simultaneously, study on molecular mechanism of RNAi, which might be involved in the level of post-transcription, translation, genome methylation or conduction of silencing signals, is now making unceasing progress. Clear elucidation of the molecular mechanism could provide important theoretical references and powerful tools for the practical application in this field where RNAi may be put into the use of systematic gene screening, the discovery of new genes and the gene therapy for human tumor or other refractory human diseases.
Animals ; DNA Methylation ; Humans ; MicroRNAs ; metabolism ; RNA Interference

Hepatitis B ; virology ; Hepatitis B virus ; RNA Interference

The small RNAs include siRNA and miRNA. SiRNA is the splicing product of exogenous dsRNA by which to keep genome stability, while miRNA are processed from endogenous genome and work as a post-transcriptional regulator for gene expression. The small RNAs act in two ways: mediate degradation of of target RNA and inhibit translation of protein. The former requires the accurate complementation between small RNA and target RNA, while the latter requires only partial complementation. Which mechanism used depends on complementation degree, but not their origins. The RNAi as a technique for down-regulating target gene expression has been widely used in functional genomic studies and hematologic studies, especially for translocation-related fusion gene, apoptosis-related gene and MDR gene in leukemia. The results show that RNAi technique not only is the powerful tool for study mechanism but also has therapeutic potentials in clinic. Some studies reveal that changes of miRNA expression exist in many hematological malignancies and relate to known oncogenes, which indicates the miRNA is involved in pathogenesis of these diseases. This article reviews the discovery and effect of RNAi and small RNAs, as well as the similarities and differences between siRNA and miRNA, and focuses on the research of small RNAs in hematological malignancies.
Hematologic Neoplasms ; genetics ; Humans ; MicroRNAs ; genetics ; RNA ; genetics ; RNA Interference ; RNA, Small Interfering ; genetics