Minisymposium 6: Epigenetics

Abs # 16002: Gene-specific suppression of a multigene family in plants by RNA silencing and its epigenetic effects on the target genes

Presenter:	Miki, Daisuke , d-miki@bs.aist-nara.ac.jp
Authors	Miki, Daisuke  (A)   Itoh, Rika  (A)   Moritoh, Satoru  (A)   Shimamoto, Ko  (A)
Affiliations:	(A): Nara Institute of Science and Technology (NAIST)

RNA silencing with inverted repeat (IR) constructs has been used to suppress gene function in various organisms. However, the secondary (transitive) RNA silencing described in C. elegans and plants may preclude the use of RNA silencing for a gene family. To address this question, we designed IR constructs of unique 3’ UTRs derived from the rice OsRac gene family, and transformed them into rice. Each of the seven members of the OsRac gene family was specifically suppressed by its respective IR construct in transgenic rice. Spreading of short interfering RNA (siRNA) was not observed along OsRac mRNA. Use of highly conserved regions of the two members of the OsRac gene family also suppressed the expression of all the members of the gene family with variable efficiencies. Analysis of DNA methylation in the RNA silencing transgenic rice showed that the target endogenous genes were not as readily methylated as the IR transgenes. However, de novo CpG methylation was preferentially increased in 4 of 5 target genes examined. Together our results indicated that RNA silencing with IR constructs is a useful tool for the analysis of a gene family in plants.