SANTA CRUZ, Calif., July 24, 2012 /PRNewswire/ -- SomaGenics, Inc., a biotechnology company specializing in RNA-based technologies, announced the publication of a study reporting the mechanism of action of its sshRNAs, the class of molecules that forms the basis of the company's therapeutic platform. sshRNAs are small synthetic stem-loop (or hairpin) RNAs that the company's researchers have shown to be highly potent in knocking down target RNAs through an RNA interference (RNAi) mechanism. In the new study, the SomaGenics authors and their collaborators show that the two structurally distinct types of sshRNA, right-loop or R-type and left-loop or L-type, have different mechanisms of action, and each is different from the mechanisms of action of standard siRNAs and shRNAs.
The new study shows that sshRNAs do not require the enzyme Dicer for activity in cells, unlike standard larger hairpin RNAs and most microRNAs. Other results show that R- and L-type sshRNAs require different structural features to be highly active, and provide an explanation for how these features promote the gene silencing potency of each class of molecules. R-sshRNAs require that their loops be cleavable by a non-Dicer cellular enzyme for maximal activity, whereas L-sshRNAs function very well with their loops intact. In both types of hairpins, the non-active, "passenger" sequence is "sliced" by the key enzyme Argonaute-2, but in the case of L-sshRNAs, only the single small fragment of slicing is lost from the RNA-induced silencing complex (RISC) prior to engaging the target to be silenced, while for R-sshRNAs and siRNAs, two small fragments of slicing are removed. Interestingly, L-sshRNAs have a natural equivalent, the recently discovered microRNA miR-451, which also does not require Dicer activity to be incorporated into the RNAi machinery.
The new study appears online this week in Nucleic Acids Research. The lead author is Dr. Anne Dallas of SomaGenics, and
|SOURCE SomaGenics, Inc.|
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