Epigenetic Regulation of Intronic Transgenes in Arabidopsis

• Published in: Scientific reports Vol. 7; no. 1; p. 45166
• Main Authors: Osabe, Kenji, Harukawa, Yoshiko, Miura, Saori, Saze, Hidetoshi
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 24.03.2017; Nature Publishing Group
• Subjects: 38/22; 38/23; 38/77; 42/70; 631/208/2491/2046; 631/449; Arabidopsis - genetics; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Defense mechanisms; Deoxyribonucleic acid; DNA; DNA methylation; Downy mildew; Epigenesis, Genetic; Genes; Genomes; Humanities and Social Sciences; Introns; Jumonji Domain-Containing Histone Demethylases - genetics; Jumonji Domain-Containing Histone Demethylases - metabolism; multidisciplinary; Nucleotide sequence; Science; T-DNA; Transcription; Transcription Factors - genetics; Transcription Factors - metabolism; Transgenes; Transgenic plants
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep45166

Defense mechanisms of plant genomes can epigenetically inactivate repetitive sequences and exogenous transgenes. Loss of mutant phenotypes in intronic T-DNA insertion lines by interaction with another T-DNA locus, termed T-DNA suppression, has been observed in Arabidopsis thaliana , although the molecular basis of establishment and maintenance of T-DNA suppression is poorly understood. Here we show that maintenance of T-DNA suppression requires heterochromatinisation of T-DNA sequences and the nuclear proteins, INCREASED IN BONSAI METHYLATION 2 (IBM2) and ENHANCED DOWNY MILDEW 2 (EDM2), which prevent ectopic 3′ end processing of mRNA in atypically long introns containing T-DNA sequences. Initiation of T-DNA suppression is mediated by the canonical RdDM pathway after hybridisation of two T-DNA strains, accompanied by DNA hypermethylation of T-DNA sequences in the F1 generation. Our results reveal the presence of a genome surveillance mechanism through genome hybridisation that masks repetitive DNAs intruding into transcription units.