TY - JOUR
T1 - Transcriptional gene silencing by Arabidopsis microrchidia homologues involves the formation of heteromers
AU - Moissiard, Guillaume
AU - Bischof, Sylvain
AU - Husmann, Dylan
AU - Pastor, William A.
AU - Hale, Christopher J.
AU - Yen, Linda
AU - Stroud, Hume
AU - Papikian, Ashot
AU - Vashisht, Ajay A.
AU - Wohlschlegel, James A.
AU - Jacobsen, Steven E.
PY - 2014/5/20
Y1 - 2014/5/20
N2 - Epigenetic gene silencing is of central importance to maintain genome integrity and is mediated by an elaborate interplay between DNA methylation, histone posttranslational modifications, and chromatin remodeling complexes. DNA methylation and repressive histone marks usually correlate with transcriptionally silent heterochromatin, however there are exceptions to this relationship. In Arabidopsis, mutation of Morpheus Molecule 1 (MOM1) causes transcriptional derepression of heterochromatin independently of changes in DNA methylation. More recently, two Arabidopsis homologues of mouse microrchidia (MORC) genes have also been implicated in gene silencing and heterochromatin condensation without altering genome-wide DNA methylation patterns. In this study, we show that Arabidopsis microrchidia (AtMORC6) physically interacts with AtMORC1 and with its close homologue, AtMORC2, in two mutually exclusive protein complexes. RNA-sequencing analyses of high-order mutants indicate that AtMORC1 and AtMORC2 act redundantly to repress a common set of loci. We also examined genetic interactions between AtMORC6 and MOM1 pathways. Although AtMORC6 and MOM1 control the silencing of a very similar set of genomic loci, we observed synergistic transcriptional regulation in the mom1/atmorc6 double mutant, suggesting that these epigenetic regulators act mainly by different silencing mechanisms.
AB - Epigenetic gene silencing is of central importance to maintain genome integrity and is mediated by an elaborate interplay between DNA methylation, histone posttranslational modifications, and chromatin remodeling complexes. DNA methylation and repressive histone marks usually correlate with transcriptionally silent heterochromatin, however there are exceptions to this relationship. In Arabidopsis, mutation of Morpheus Molecule 1 (MOM1) causes transcriptional derepression of heterochromatin independently of changes in DNA methylation. More recently, two Arabidopsis homologues of mouse microrchidia (MORC) genes have also been implicated in gene silencing and heterochromatin condensation without altering genome-wide DNA methylation patterns. In this study, we show that Arabidopsis microrchidia (AtMORC6) physically interacts with AtMORC1 and with its close homologue, AtMORC2, in two mutually exclusive protein complexes. RNA-sequencing analyses of high-order mutants indicate that AtMORC1 and AtMORC2 act redundantly to repress a common set of loci. We also examined genetic interactions between AtMORC6 and MOM1 pathways. Although AtMORC6 and MOM1 control the silencing of a very similar set of genomic loci, we observed synergistic transcriptional regulation in the mom1/atmorc6 double mutant, suggesting that these epigenetic regulators act mainly by different silencing mechanisms.
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U2 - 10.1073/pnas.1406611111
DO - 10.1073/pnas.1406611111
M3 - Article
C2 - 24799676
AN - SCOPUS:84901044582
SN - 0027-8424
VL - 111
SP - 7474
EP - 7479
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 20
ER -