Here we report a versatile mammalian expression vector called pRIGHT11 for production of small interfering RNA (siRNA) in cells. This vector uses opposing eukaryotic RNA polymerase III promoters U6 and H1 to drive the expression of short siRNA. We have demonstrated the effectiveness of pRIGHT11-generated siRNA in sequence-specific inhibition of transfected reporter genes and endogenous genes. F...

The enzyme Dicer produces small silencing RNAs such as micro-RNAs (miRNAs) and small interfering RNAs (siRNAs). In Drosophila, Dicer-1 produces ∼22-24-nt miRNAs from pre-miRNAs, whereas Dicer-2 makes 21-nt siRNAs from long double-stranded RNAs (dsRNAs). How Dicer-2 precisely makes 21-nt siRNAs with a remarkably high fidelity is unknown. Here we report that recognition of the 5'-monophosphate of...

Two classes of small RNAs, microRNAs and short-interfering RNA (siRNAs), have been extensively studied in plants and animals. In Arabidopsis, the capacity to uncover previously uncharacterized small RNAs by means of conventional strategies seems to be reaching its limits. To discover new plant small RNAs, we developed a protocol to mine an Arabidopsis nonannotated, noncoding EST database. Using...

Small RNA guides--microRNAs, small interfering RNAs, and repeat-associated small interfering RNAs, 21 to 30 nucleotides in length--shape diverse cellular pathways, from chromosome architecture to stem cell maintenance. Fifteen years after the discovery of RNA silencing, we are only just beginning to understand the depth and complexity of how these RNAs regulate gene expression and to consider t...

Chemically modified siRNAs are expected to have resistance toward nuclease degradation and good thermal stability in duplex formation for in vivo applications. We have recently found that 2'-OMe-4'-thioRNA, a hybrid chemical modification based on 2'-OMeRNA and 4'-thioRNA, has high hybridization affinity for complementary RNA and significant resistance toward degradation in human plasma. These r...

RNA silencing phenomena were first discovered in plants, yet only the RNA interference pathway in animals has been subject to biochemical analysis. Here, we extend biochemical analysis to plant RNA silencing. We find that standard wheat germ extract contains Dicer-like enzymes that convert double-stranded RNA (dsRNA) into two classes of small interfering RNAs, as well as an RNA-dependent RNA po...

Loosely aggregated conjugated polymer nanoparticles (CPNs) were used as nontoxic and efficient small interfering RNA (siRNA) delivery vehicles with delivery visualization. A significant down regulation (94%) of a target gene was achieved by transfection of HeLa cells with the CPNs/siRNA complexes, supporting CPN as a promising siRNA delivery carrier.

It has been shown that Osteopontin (OPN) protein is overexpressed in the majority of gastric cancers and associated with its pathogenesis. To better understanding of the role of OPN, RNA interference (RNAi) was used to inhibit OPN expression in the human gastric cancer cells in vitro and in vivo. BGC-823, gastric cancer cell line, was stably transfected with OPN small interfering RNA (siRNA) pl...