genetic rearrangements can modify chromatin features at epialleles基因重组可以修改染色质在epialleles特性.pdfVIP

Genetic Rearrangements Can Modify Chromatin Features at Epialleles 1 1,2 1 1 1 Andrea M. Foerster , Huy Q. Dinh , Laura Sedman , Bonnie Wohlrab , Ortrun Mittelsten Scheid * 1 Gregor Mendel Institute of Molecular Plant Biology (GMI), Austrian Academy of Sciences, Vienna, Austria, 2 Center for Integrative Bioinformatics Vienna, Max F. Perutz Laboratories (MFPL), Vienna, Austria Abstract Analogous to genetically distinct alleles, epialleles represent heritable states of different gene expression from sequence- identical genes. Alleles and epialleles both contribute to phenotypic heterogeneity. While alleles originate from mutation and recombination, the source of epialleles is less well understood. We analyze active and inactive epialleles that were found at a transgenic insert with a selectable marker gene in Arabidopsis. Both converse expression states are stably transmitted to progeny. The silent epiallele was previously shown to change its state upon loss-of-function of trans-acting regulators and drug treatments. We analyzed the composition of the epialleles, their chromatin features, their nuclear localization, transcripts, and homologous small RNA. After mutagenesis by T-DNA transformation of plants carrying the silent epiallele, we found new active alleles. These switches were associated with different, larger or smaller, and non- overlapping deletions or rearrangements in the 39 regions of the epiallele. These cis-mutations caused different degrees of gene expression stability depending on the nature of the sequence alteration, the consequences for transcription and transcripts, and the resulting chromatin organiz