Accumulation of transgene-derived siRNAs is not sufficient for RNAi-mediated protection againstCitrus tristeza virusin transgenic Mexican lime

Tsix-mediated repression of Xist accumulation is not sufficient for normal random X inactivation.

During the X inactivation process, one X chromosome in each female embryonic cell is chosen at random to become coated by Xist RNA and silenced. Tsix, a transcript anti-sense to Xist, participates in the choice of the inactive X and in Xist regulation through as yet unknown mechanisms. Undifferentiated female ES cells, which have two active Xs, recapitulate random X inactivation when induced to...

RNAi – Is one suffix sufficient?

RNA-directed translational gene silencing in many organisms appears to represent a later evolved function for this versatile molecule, and the observation that protein domains similar to those of RISC complex components in Tetrahymena, fission yeast, fungi and archaeal bacteria suggests that RNA interference as it is currently understood may have developed as a functional entity in the last com...

Dicer's helicase domain is required for accumulation of some, but not all, C. elegans endogenous siRNAs.

Years after the discovery that Dicer is a key enzyme in gene silencing, the role of its helicase domain remains enigmatic. Here we show that this domain is critical for accumulation of certain endogenous small interfering RNAs (endo-siRNAs) in Caenorhabditis elegans. The domain is required for the production of the direct products of Dicer, or primary endo-siRNAs, and consequently affects level...

Development of Transgenic Mice Harboring Ovine Beta Lactoglobulin-Calcitonin Transgene

Single-Stranded siRNAs Activate RNAi in Animals

The therapeutic utility of siRNAs is limited by the requirement for complex formulations to deliver them to tissues. If potent single-stranded RNAs could be identified, they would provide a simpler path to pharmacological agents. Here, we describe single-stranded siRNAs (ss-siRNAs) that silence gene expression in animals absent lipid formulation. Effective ss-siRNAs were identified by iterative...