Summary: Histone arginine methylation is required for
vernalization-induced epigenetic silencing of
FLC in winter-annual Arabidopsis thaliana
Robert J. Schmitz*, Sibum Sung
, and Richard M. Amasino*§
*Laboratory of Genetics and Department of Biochemistry, University of Wisconsin, Madison, WI 53706
This contribution is part of the special series of Inaugural Articles by members of the National Academy of Sciences elected on April 25, 2006.
Contributed by Richard M. Amasino, November 2, 2007 (sent for review September 6, 2007)
Certain plant varieties typically require prolonged exposure to the
cold of winter to become competent to flower rapidly in the spring.
This process is known as vernalization. In Arabidopsis thaliana,
vernalization renders plants competent to flower by epigenetically
silencing the strong floral repressor FLOWERING LOCUS C (FLC). As
a result of vernalization, levels of lysine-9 and lysine-27 trimethy-
lation on histone 3, modifications that are characteristic of facul-
tative heterochromatin in plants, increase at FLC chromatin. We
have identified a mutant, protein arginine methyltransferase 5
(atprmt5), that fails to flower rapidly after vernalization treatment.
AtPRMT5 encodes a type II protein arginine methyltransferase
(PRMT) that, in winter-annual strains, is required for epigenetic