RT Journal Article
SR Electronic
T1 Polycomb mutant partially suppresses DNA hypomethylation–associated phenotypes in Arabidopsis
JF Life Science Alliance
JO Life Sci. Alliance
FD Life Science Alliance LLC
SP e202000848
DO 10.26508/lsa.202000848
VO 4
IS 2
A1 Martin Rougée
A1 Leandro Quadrana
A1 Jérôme Zervudacki
A1 Valentin Hure
A1 Vincent Colot
A1 Lionel Navarro
A1 Angélique Deleris
YR 2021
UL https://www.life-science-alliance.org/content/4/2/e202000848.abstract
AB In plants and mammals, DNA methylation and histone H3 lysine 27 trimethylation (H3K27me3), which is deposited by the polycomb repressive complex 2, are considered as two specialized systems for the epigenetic silencing of transposable element (TE) and genes, respectively. Nevertheless, many TE sequences acquire H3K27me3 when DNA methylation is lost. Here, we show in Arabidopsis thaliana that the gain of H3K27me3 observed at hundreds of TEs in the ddm1 mutant defective in the maintenance of DNA methylation, essentially depends on CURLY LEAF (CLF), one of two partially redundant H3K27 methyltransferases active in vegetative tissues. Surprisingly, the complete loss of H3K27me3 in ddm1 clf double mutant plants was not associated with further reactivation of TE expression nor with a burst of transposition. Instead, ddm1 clf plants exhibited less activated TEs, and a chromatin recompaction as well as hypermethylation of linker DNA compared with ddm1. Thus, a mutation in polycomb repressive complex 2 does not aggravate the molecular phenotypes linked to ddm1 but instead partially suppresses them, challenging our assumptions of the relationship between two conserved epigenetic silencing pathways.