PT - JOURNAL ARTICLE AU - Pierre Bourguet AU - Stève de Bossoreille AU - Leticia López-González AU - Marie-Noëlle Pouch-Pélissier AU - Ángeles Gómez-Zambrano AU - Anthony Devert AU - Thierry Pélissier AU - Romain Pogorelcnik AU - Isabelle Vaillant AU - Olivier Mathieu TI - A role for MED14 and UVH6 in heterochromatin transcription upon destabilization of silencing AID - 10.26508/lsa.201800197 DP - 2018 Dec 01 TA - Life Science Alliance PG - e201800197 VI - 1 IP - 6 4099 - https://www.life-science-alliance.org/content/1/6/e201800197.short 4100 - https://www.life-science-alliance.org/content/1/6/e201800197.full SO - Life Sci. Alliance2018 Dec 01; 1 AB - Constitutive heterochromatin is associated with repressive epigenetic modifications of histones and DNA which silence transcription. Yet, particular mutations or environmental changes can destabilize heterochromatin-associated silencing without noticeable changes in repressive epigenetic marks. Factors allowing transcription in this nonpermissive chromatin context remain poorly known. Here, we show that the transcription factor IIH component UVH6 and the mediator subunit MED14 are both required for heat stress–induced transcriptional changes and release of heterochromatin transcriptional silencing in Arabidopsis thaliana. We find that MED14, but not UVH6, is required for transcription when heterochromatin silencing is destabilized in the absence of stress through mutating the MOM1 silencing factor. In this case, our results raise the possibility that transcription dependency over MED14 might require intact patterns of repressive epigenetic marks. We also uncover that MED14 regulates DNA methylation in non-CG contexts at a subset of RNA-directed DNA methylation target loci. These findings provide insight into the control of heterochromatin transcription upon silencing destabilization and identify MED14 as a regulator of DNA methylation.