bioRxiv preprint doi: https://doi.org/10.1101/407015; this version posted September 3, 2018. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. Differential requirement of MED14 and UVH6 for heterochromatin transcription upon destabilization of silencing Pierre Bourguet1, Stève de Bossoreille1,2†, Leticia López-González1†, Marie-Noëlle Pouch-Pélissier1, Ángeles Gómez-Zambrano1,3, Anthony Devert1, Thierry Pélissier1, Romain Pogorelcnik1, Isabelle Vaillant1, Olivier Mathieu1* 1 Université Clermont Auvergne, CNRS, Inserm, Génétique Reproduction et Développement (GReD), F-63000 Clermont- Ferrand, France 2 Present address: Laboratoire Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRA, F-69342, Lyon, France 3 Present address: Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC-Cartuja, Avda. Américo Vespucio, 49. 41092- Sevilla- Spain † These authors contributed equally to this work * Corresponding author. Tel: 33 473 407 407, E-mail:
[email protected] Abstract Constitutive heterochromatin is commonly associated with high levels of repressive epigenetic marks and is stably maintained transcriptionally silent by the concerted action of different, yet convergent, silencing pathways. Reactivation of heterochromatin transcription is generally associated with alterations in levels of these epigenetic marks. However, in mutants for particular epigenetic regulators, or upon particular environmental changes such as heat stress, heterochromatin-associated silencing is destabilized without noticeable changes in epigenetic marks. This suggests that transcription can occur in a non-permissive chromatin context, yet the factors involved remain poorly known.