W709 Transposon activation in Arabidopsis allopolyploids is mediated by RNA interference

Date: Sunday, January 15, 2012
Time: 2:30 PM
Room: Golden Ballroom
Rob Martienssen , Cold Spring Harbor Laboratory, Cold Spring Harbor, NY
Milos Tanurdzic , Cold Spring Harbor Laboratory, Cold Spring Harbor, NY
Paul Auer , Purdue University, West Lafayette, IN
Patrick Finigan , Cold Spring Harbor Laboratory, Cold Spring Harbor, NY
Evan Ernst , Cold Spring Harbor Laboratory, Cold Spring Harbor, NY
Brian P. Dilkes , Purdue University, West Lafayette, IN
Luca Comai , UC Davis, Davis, CA
Blake C. Meyers , University Delaware, Newark, DE
Matt Vaughn , Texas Advances Computing Ctr, University of Texas, Austin, TX
Rebecca Doerge , Purdue University, West Lafayette, IN
Silencing of transposable elements lowers the mutagenic effects of transposition, but requires that TEs are recognized by the survelliance machinery. We have found that a specific class of COPIA retrotransposons  are activated in Arabidopsis inter-specific polyploid hybrids, but only when matching small interfering RNA (siRNA) are absent from the seed parent. These COPIA elements lose DNA methylation, and hybrids accumulate 21nt "epigenetically activated siRNA" (easiRNA) normally found in pollen.  They also accumulate extra-chromosomal cDNA transposition intermediates indicative of active transposition.  Our results indicate that small RNA provides a recognition mechanism for transposons in inter-specific hybrids, reminiscent of hybrid dysgenesis and hybrid lethality in Drosophila, and may contribute to post-fertilization hybridization barriers in a similar way.