000			02061nam a2200265Ia 4500
008			220216s9999 xx 000 0 und d
100			_aVermeersch Leen
245		0	_aTransitive RNA silencing signals induce cytosine methylation of a transgenic but not an endogenous target
260			_bThe Plant Journal _c2013
300			_a867-879
520			_aPost-transcriptional gene silencing of a primary target gene in plants can coincide with the production of secondary small interfering RNAs (siRNAs) of coding sequences adjacent to the target region and with de novo RNA-directed DNA methylation (RdDM) thereof. Here, we analyzed the susceptibility of transgenic and endogenous targets to RdDM induced by primary and seconday silencing signals. In three different configurations, primary silencing signals were able t direct in trans methylation of chimeric transgenes and the CATALASE2 (CAT2) endogene; however, extensive spreading of methylation occured only in the transgene, resulting in the methylation of the flanking CAT2 sequence, whereas methylation of the CAT2 endogene was restricted to the target region and the enclosed introns. The secondary silencing signals arising from this transgenic primary target simultaneously silenced a secondary transgene target and the CAT2 endogene, but were only capable of directing RdDM to the transgene. Our data indicate that RdDM is correlated with the in situ generation of secondary siRNAs, occuring in P35S-driven transgenes but not in most endogenes. We conclude that although both endogenes are equally sensitive to transitive silencing, differences exist in their susceptibility to undergo secondary RdDM.
650			_aArbidopsis thaliana
650			_aEndogene
650			_aIntron
650			_aPost-transcriptional gene silencing
650			_aRNA-directed DNA methylation
650			_aTransgene
650			_aTransitive silencing
700			_aBleys Annick
700			_aDepicker Ann
700			_aKovarik Ales
700			_aNolf Jonah
700			_aWinne Nancy De
942			_cJS
999			_c71490 _d71490