INVESTIGADORES
CASATI Paula
artículos
Título:
Mutator transposon activation after UV-B involves chromatin remodeling
Autor/es:
JULIA I. QÜESTA; VIRGINIA WALBOT; PAULA CASATI
Revista:
EPIGENETICS
Editorial:
LANDES BIOSCIENCE
Referencias:
Año: 2010 vol. 5 p. 1 - 12
ISSN:
1559-2294
Resumen:
spontaneous silencing of MuDR/Mu transposons occurs in ∼10–100% of the progeny of an active plant, and once silenced reactivation is very rare. To date, only radiation treatments have reactivated silenced Mu; for example UV-B radiation reactivated Mutator activities. Hhere we have investigated possible mechanisms by which UV-B could reactivate Mu transposons by monitoring transcript abundance, epigenetic DNAa marks, and chromatin factors associated with these elements. We demonstrate that both mudrA and B transcripts are expressed at higher levels after an 8 h-UV-B treatment, in both active Mutator and silencing plants, and that different chromatin remodeling events occur in the promoter regions of MuDR than in non-autonomous Mu1 elements. Increased transcript abundance is accompanied by an increase in histone Hh3 acetylation and by decreased DNAa and Hh3K9me2 methylation. No changes in siRNAa levels were detected. In contrast, the decrease in present at Mu elements after UV-B is significant in silencing plants, suggesting that early changes in methylation in K9, chromatin remodeling, and transcription factor binding contribute directly to transposon reactivation by UV-B in maize.