TY - JOUR
T1 - H3K9me-independent gene silencing in fission yeast heterochromatin by Clr5 and histone deacetylases
AU - Hansen, Klavs R
AU - Hazan, Idit
AU - Shanker, Sreenath
AU - Watt, Stephen
AU - Hansen, Janne Verhein
AU - Bähler, Jürg
AU - Martienssen, Robert A
AU - Partridge, Janet F
AU - Cohen, Amikam
AU - Thon, Genevieve
N1 - Artikel ID: e1001268
PY - 2011
Y1 - 2011
N2 - Nucleosomes in heterochromatic regions bear histone modifications that distinguish them from euchromatic nucleosomes. Among those, histone H3 lysine 9 methylation (H3K9me) and hypoacetylation have been evolutionarily conserved and are found in both multicellular eukaryotes and single-cell model organisms such as fission yeast. In spite of numerous studies, the relative contributions of the various heterochromatic histone marks to the properties of heterochromatin remain largely undefined. Here, we report that silencing of the fission yeast mating-type cassettes, which are located in a well-characterized heterochromatic region, is hardly affected in cells lacking the H3K9 methyltransferase Clr4. We document the existence of a pathway parallel to H3K9me ensuring gene repression in the absence of Clr4 and identify a silencing factor central to this pathway, Clr5. We find that Clr5 controls gene expression at multiple chromosomal locations in addition to affecting the mating-type region. The histone deacetylase Clr6 acts in the same pathway as Clr5, at least for its effects in the mating-type region, and on a subset of other targets, notably a region recently found to be prone to neo-centromere formation. The genomic targets of Clr5 also include Ste11, a master regulator of sexual differentiation. Hence Clr5, like the multi-functional Atf1 transcription factor which also modulates chromatin structure in the mating-type region, controls sexual differentiation and genome integrity at several levels. Globally, our results point to histone deacetylases as prominent repressors of gene expression in fission yeast heterochromatin. These deacetylases can act in concert with, or independently of, the widely studied H3K9me mark to influence gene silencing at heterochromatic loci.
AB - Nucleosomes in heterochromatic regions bear histone modifications that distinguish them from euchromatic nucleosomes. Among those, histone H3 lysine 9 methylation (H3K9me) and hypoacetylation have been evolutionarily conserved and are found in both multicellular eukaryotes and single-cell model organisms such as fission yeast. In spite of numerous studies, the relative contributions of the various heterochromatic histone marks to the properties of heterochromatin remain largely undefined. Here, we report that silencing of the fission yeast mating-type cassettes, which are located in a well-characterized heterochromatic region, is hardly affected in cells lacking the H3K9 methyltransferase Clr4. We document the existence of a pathway parallel to H3K9me ensuring gene repression in the absence of Clr4 and identify a silencing factor central to this pathway, Clr5. We find that Clr5 controls gene expression at multiple chromosomal locations in addition to affecting the mating-type region. The histone deacetylase Clr6 acts in the same pathway as Clr5, at least for its effects in the mating-type region, and on a subset of other targets, notably a region recently found to be prone to neo-centromere formation. The genomic targets of Clr5 also include Ste11, a master regulator of sexual differentiation. Hence Clr5, like the multi-functional Atf1 transcription factor which also modulates chromatin structure in the mating-type region, controls sexual differentiation and genome integrity at several levels. Globally, our results point to histone deacetylases as prominent repressors of gene expression in fission yeast heterochromatin. These deacetylases can act in concert with, or independently of, the widely studied H3K9me mark to influence gene silencing at heterochromatic loci.
KW - Amino Acid Sequence
KW - Chromosomal Proteins, Non-Histone
KW - Gene Expression Regulation, Fungal
KW - Gene Silencing
KW - Heterochromatin
KW - Histone Deacetylases
KW - Histone-Lysine N-Methyltransferase
KW - Histones
KW - Methylation
KW - Molecular Sequence Data
KW - Mutation
KW - Schizosaccharomyces
KW - Schizosaccharomyces pombe Proteins
KW - Sequence Alignment
KW - Sequence Homology, Amino Acid
KW - Transcription Factors
U2 - 10.1371/journal.pgen.1001268
DO - 10.1371/journal.pgen.1001268
M3 - Journal article
C2 - 21253571
SN - 1553-7390
VL - 7
JO - P L o S Genetics
JF - P L o S Genetics
IS - 1
ER -