Patent ID: 7267979
Filing Date: 2007-09-11
Classification: C12N

Abstract:
1. A gene silencing site-specific recombination system comprising: a) a first recombinase element having the general structure P1-R, wherein P1 is a first promoter and R is a recombinase coding sequence and 3′ region; and b) a second recombinase element having the general structure: RS-X-RS*-Y wherein: i) RS and RS* are opposingly oriented recombinase sites responsive to the recombinase; ii) X is a nucleic acid fragment comprising at least one second promoter in a 3′ to 5′ orientation, wherein X comprises 5′ Intron-TSINV-P2INV; and iii) Y is a nucleic acid fragment comprising 3′ Intron-TSINV-polyA; wherein: 1) P2INV comprises an inverted second promoter whose orientation is from 3′-5′; 2) TSINV is an inverted target sequence whose orientation is from 3′-5′, and is complementary to a sequence in the coding region of a target gene; 3) polyA is the 3′ region of a gene; 4) 5′ Intron is the N-terminal portion of an intron; and, 5) 3′ Intron is the C-terminal portion of said intron; wherein, when said system is present in a plant cell comprising the target gene, expression of the recombinase results in inversion of X, yielding a recombined second recombinase element, RS-P2-TS-5′ Intron-RS*-3′ Intron-TSINV-polyA, wherein transcription of TS and TSINV by P2 results in the production of double-stranded RNA that causes silencing of the target gene.