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Local DNA features affect RNA‐directed transcriptional gene silencing and DNA methylation
Author(s) -
Fischer Ute,
Kuhlmann Markus,
Pecinka Ales,
Schmidt Renate,
Mette Michael F.
Publication year - 2008
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/j.1365-313x.2007.03311.x
Subject(s) - gene silencing , biology , dna methylation , transgene , rna silencing , methylation , genetics , rna induced silencing complex , microbiology and biotechnology , transcription (linguistics) , gene , rna , promoter , rna interference , gene expression , linguistics , philosophy
Summary Transcription of a nopaline synthase promoter (pNOS) inverted repeat provides an RNA signal that can trigger transcriptional gene silencing and methylation of pNOS promoters in trans . The degree of silencing is influenced by the local DNA features close to the target promoter integration sites. Among 26 transgenic Arabidopsis thaliana lines harbouring single copies of a T‐DNA including a pNOS‐ NPTII reporter gene at different chromosomal loci, NPTII RNA levels showed limited variation. When challenged by the silencer transgene providing the pNOS RNA signal, reduction of the NPTII RNA levels in the F 1 generation varied by more than 100‐fold, ranging from no reduction to reduction to <1% of the non‐silenced level. Silencing was generally correlated with proportional DNA methylation in the pNOS region, except for one target transgene showing substantial DNA methylation without adequate silencing. Silencing was progressive through generations. Differences in the degree of silencing among the target transgenes were transmitted at least to the F 3 generation, and seemed to be influenced by transgene‐flanking sequences. Apparently, close‐by repeats promoted, whereas close‐by functional genes diminished, the response to the silencing signal.