A patent application covering nucleic acid and protein sequences related to a gene required for systemic RNAi was published by the USPTO on Sept. 4.
The application — number 20030167490 — was filed on Nov. 26, 2002, and cites Craig Hunter and colleagues at Harvard’s Department of Molecular and Cellular Biology as inventors.
According to the application, RNAi-based gene silencing can spread throughout organisms such as C. elegans and be passed on from parent to progeny. This phenomenon, however, "does not appear to act stoichiometrically,” the application stated.
“It has been suggested that the RNA is acting catalytically and/or is replicated by cellular proteins. However, the mechanism of systemic RNAi and genes involved in mediating systemic RNAi have not been identified to date.”
The application states that the inventors have linked systemic RNAi to a gene termed sid-1, because cells missing the gene or the protein it encodes — called SID-1 — are systemic RNA interference deficient.
“SID-1 is found in organisms where systemic RNA interference is observed, such as C. elegans, but not in organisms where systemic RNA interference is not found, such as Drosophila melanogaster” the application states. “Elimination of sid-1 in isolated cells in culture also inhibits RNAi in cells exposed to a double-stranded (dsRNA) in the culture medium. Thus, SID-1 is involved in importing and/or processing the systemic RNAi signal across a cell membrane.”
Specifically, the patent application claims “nucleic acids, vectors, transformed cells, transgenic animals, polypeptides, and antibodies relating to the sid-1 gene and protein,” which the inventors state is required for systemic RNAi.
The application also provides for “methods for reducing the expression of a target gene in a cell, population of cells, or an animal.”