Natural variation in DNA methylation homeostasis and the emergence of epialleles

• DOI: 10.1073/pnas.1918172117
• Publication Date: 2020-02-18T23:15:39Z
• Authors: Yinwen Zhang; Jered M. Wendte; Lexiang Ji; Robert J. Schmitz
• Keywords: Euchromatin; Epigenomics; Heterochromatin protein 1

In plants and mammals, DNA methylation plays a critical role in transcriptional silencing by delineating heterochromatin from transcriptionally active euchromatin. A homeostatic balance between euchromatin is essential to genomic stability. This evident many diseases mutants for maintenance, which are characterized global losses of coupled with localized ectopic gains that alter transcription. Furthermore, we have shown genome-wide patterns Arabidopsis thaliana highly stable over generations, the exception rare epialleles. However, extent natural variation robustness targeting exists, phenotypic consequences such variation, remain be fully explored. Here describe finding genic variable among 725 A. accessions. We found inversely correlated heterochromatin, suggesting certain pathway(s) may redirected genes upon loss heterochromatin. redistribution likely involves feedback loop involving methyltransferase, CHROMOMETHYLASE 3 (CMT3), H3K9me2, histone turnover, as expressed, long high density CMT3-preferred CWG sites more methylated. Importantly, although presence CG alone not affect transcription, containing become methylated at non-CG silenced. These findings consistent hypothesis homeostasis underlie evolution epialleles phenotypes.