H3K9 methylation-independent activity for HPL-2/HP1 in heterochromatin foci, gene repression, and organogenesis
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PROVIDER: PRJNA1167308 | ENA |
REPOSITORIES: ENA
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Project description:Differentiated cells rely on segregation of the genome into heterochromatin and euchromatin, but the mechanisms that establish these domains in vivo are incompletely understood. The current models suggest that heterochromatin is marked by histone H3 lysine 9 methylation (H3K9me), which recruits heterochromatin protein 1 (HP1), to compact chromatin and repress transcription. In C. elegans, the SETDB1 homolog MET-2 is essential for H3K9me-mediated gene silencing; however, MET-2 also localizes to heterochromatic foci independently of H3K9me and exhibits non-catalytic functions that support both germline and somatic development. Here we extend these findings by examining the classical H3K9me reader HP1. We show that HPL-2/HP1 deficient in methyl-lysine binding or in the absence of H3K9me can still repress transcription, promote organogenesis and localize to heterochromatin foci. Whereas activity remains in the absence of the HPL-2:H3K9me interaction, complete loss of met-2 and hpl-2 shows synergistic phenotypes for organogenesis and gene de-repression, underscoring the existence of additional, H3K9me-independent functions. HPL-2 and MET-2 require distinct binding partners for their localization and activity: MET-2 associates with the disordered protein LIN-65/ATF7IP, while HPL-2 depends on the multi-zinc finger protein LIN-13, which interacts with the HPL-2 chromoshadow domain. Our findings suggest that HPL-2 and MET-2 operate in parallel pathways, localizing to heterochromatic foci and promoting gene silencing and organogenesis, with H3K9me acting as a reinforcing, but non-essential, element in these processes.
2025-07-01 | GSE278459 | GEO
Project description:Histone H3 lysine 9 (H3K9) methylation and heterochromatin protein 1 (HP1) are well conserved epigenetic silencing mark and its reader molecule, and crucial for heterochromatin formation. However, the details of the importance of H3K9 methylation and HP1 in heterochromatin formation still remain unclear. One of the reason is the redundancy problem, as there are multiple reader molecules for H3K9 methylation, including HP1, and HP1 itself functions as a hub that recruits various effector molecules. To overcome the redundancy issue, we took synthetic biology approach and introduced H3K9 methylation and HP1 into budding yeast Saccharomyces cerevisiae, which does not have this system, and examined its impact on transcription and chromatin compaction. We observed that mammalian H3K9 methyltransferase can induce genome wide H3K9 di- and tri-methylation (H3K9me2,3) in budding yeast, and that HP1 accumulates over the H3K9 methylated regions. However, H3K9 methylation occurred mainly in the gene body region of the genes and excluded around TSS where H3K9ac pre-exists. Correspondingly, expression of H3K9 methyltransferase and HP1 did not affect transcription in budding yeast, including repression. ATAC-seq analysis also showed no impact on chromatin accessibility, and Hi-C-seq analysis of chromatin 3D structure revealed no significant differences. These results suggest that even though H3K9 methylation and recruitment of HP1 play essential roles in epigenetic regulation of heterochromatin, they are not sufficient to build up heterochromatin, at least at gene body regions, and further participation of effector molecules, including downstream factors of HP1, is required.
2024-02-03 | GSE224640 | GEO
Project description:Histone H3 lysine 9 (H3K9) methylation and heterochromatin protein 1 (HP1) are well conserved epigenetic silencing mark and its reader molecule, and crucial for heterochromatin formation. However, the details of the importance of H3K9 methylation and HP1 in heterochromatin formation still remain unclear. One of the reason is the redundancy problem, as there are multiple reader molecules for H3K9 methylation, including HP1, and HP1 itself functions as a hub that recruits various effector molecules. To overcome the redundancy issue, we took synthetic biology approach and introduced H3K9 methylation and HP1 into budding yeast Saccharomyces cerevisiae, which does not have this system, and examined its impact on transcription and chromatin compaction. We observed that mammalian H3K9 methyltransferase can induce genome wide H3K9 di- and tri-methylation (H3K9me2,3) in budding yeast, and that HP1 accumulates over the H3K9 methylated regions. However, H3K9 methylation occurred mainly in the gene body region of the genes and excluded around TSS where H3K9ac pre-exists. Correspondingly, expression of H3K9 methyltransferase and HP1 did not affect transcription in budding yeast, including repression. ATAC-seq analysis also showed no impact on chromatin accessibility, and Hi-C-seq analysis of chromatin 3D structure revealed no significant differences. These results suggest that even though H3K9 methylation and recruitment of HP1 play essential roles in epigenetic regulation of heterochromatin, they are not sufficient to build up heterochromatin, at least at gene body regions, and further participation of effector molecules, including downstream factors of HP1, is required.
2024-02-03 | GSE224639 | GEO
Project description:Histone H3 lysine 9 (H3K9) methylation and heterochromatin protein 1 (HP1) are well conserved epigenetic silencing mark and its reader molecule, and crucial for heterochromatin formation. However, the details of the importance of H3K9 methylation and HP1 in heterochromatin formation still remain unclear. One of the reason is the redundancy problem, as there are multiple reader molecules for H3K9 methylation, including HP1, and HP1 itself functions as a hub that recruits various effector molecules. To overcome the redundancy issue, we took synthetic biology approach and introduced H3K9 methylation and HP1 into budding yeast Saccharomyces cerevisiae, which does not have this system, and examined its impact on transcription and chromatin compaction. We observed that mammalian H3K9 methyltransferase can induce genome wide H3K9 di- and tri-methylation (H3K9me2,3) in budding yeast, and that HP1 accumulates over the H3K9 methylated regions. However, H3K9 methylation occurred mainly in the gene body region of the genes and excluded around TSS where H3K9ac pre-exists. Correspondingly, expression of H3K9 methyltransferase and HP1 did not affect transcription in budding yeast, including repression. ATAC-seq analysis also showed no impact on chromatin accessibility, and Hi-C-seq analysis of chromatin 3D structure revealed no significant differences. These results suggest that even though H3K9 methylation and recruitment of HP1 play essential roles in epigenetic regulation of heterochromatin, they are not sufficient to build up heterochromatin, at least at gene body regions, and further participation of effector molecules, including downstream factors of HP1, is required.
2024-02-03 | GSE224638 | GEO
Project description:Histone H3 lysine 9 (H3K9) methylation and heterochromatin protein 1 (HP1) are well conserved epigenetic silencing mark and its reader molecule, and crucial for heterochromatin formation. However, the details of the importance of H3K9 methylation and HP1 in heterochromatin formation still remain unclear. One of the reason is the redundancy problem, as there are multiple reader molecules for H3K9 methylation, including HP1, and HP1 itself functions as a hub that recruits various effector molecules. To overcome the redundancy issue, we took synthetic biology approach and introduced H3K9 methylation and HP1 into budding yeast Saccharomyces cerevisiae, which does not have this system, and examined its impact on transcription and chromatin compaction. We observed that mammalian H3K9 methyltransferase can induce genome wide H3K9 di- and tri-methylation (H3K9me2,3) in budding yeast, and that HP1 accumulates over the H3K9 methylated regions. However, H3K9 methylation occurred mainly in the gene body region of the genes and excluded around TSS where H3K9ac pre-exists. Correspondingly, expression of H3K9 methyltransferase and HP1 did not affect transcription in budding yeast, including repression. ATAC-seq analysis also showed no impact on chromatin accessibility, and Hi-C-seq analysis of chromatin 3D structure revealed no significant differences. These results suggest that even though H3K9 methylation and recruitment of HP1 play essential roles in epigenetic regulation of heterochromatin, they are not sufficient to build up heterochromatin, at least at gene body regions, and further participation of effector molecules, including downstream factors of HP1, is required.
2024-02-03 | GSE224636 | GEO
Project description:Linker histone H1 and heterochromatin protein 1 (HP1) are essential components ofheterochromatin which contribute to the transcriptional repression of genes. It has been shown that the methylation mark on the histone H1 serves as a specific recognition code for the chromodomain of HP1, however, the functional role of the HP1/H1 complex remains elusive. Using C. elegans, we elucidate the function of the linker histone variant HIS-24 and heterochromatin proteins HPL/HP1 in the cooperative transcriptional regulation of immunerelevant and stress resistance genes. We also show that HIS-24 and HPL act redundantly in vulval cell fate specification and gonad development. Finally, we provide the first evidence that HPL-1 interacts with HIS-24 at mono-methylated lysine 14 and associates in vivo with promoters of infection-inducible genes: the caenacin (cnc)- and the thaumatin (thn)- gene clusters. Our results highlight a functional link between epigenetic regulation by HP1/H1 the innate immune system and stress response.
2011-11-28 | GSE25714 | GEO
Project description:Linker histone H1 and heterochromatin protein 1 (HP1) are essential components ofheterochromatin which contribute to the transcriptional repression of genes. It has been shown that the methylation mark on the histone H1 serves as a specific recognition code for the chromodomain of HP1, however, the functional role of the HP1/H1 complex remains elusive. Using C. elegans, we elucidate the function of the linker histone variant HIS-24 and heterochromatin proteins HPL/HP1 in the cooperative transcriptional regulation of immunerelevant and stress resistance genes. We also show that HIS-24 and HPL act redundantly in vulval cell fate specification and gonad development. Finally, we provide the first evidence that HPL-1 interacts with HIS-24 at mono-methylated lysine 14 and associates in vivo with promoters of infection-inducible genes: the caenacin (cnc)- and the thaumatin (thn)- gene clusters. Our results highlight a functional link between epigenetic regulation by HP1/H1 the innate immune system and stress response. The experiment was performed using biological independent replicates of pooled worms. For the KO mutants we used duplicates and for WT condition quadruplicates.
2011-11-28 | E-GEOD-25714 | biostudies-arrayexpress
Project description:Activity-dependent neuroprotective protein (ADNP) is one of the most frequent autism spectrum disorder-associated gene products known to date. Here we show that Adnp interacts with the chromatin remodeler Chd4 and the heterochromatin protein HP1 to form a stable complex, which we refer to as ChAHP. Genetic ablation of ChAHP components or DNA binding sites in embryonic stem cells prematurely activates lineage-specific genes, revealing an important role for Adnp in restraining the differentiation capacity of pluripotent cells. Adnp targets the ChAHP complex to specific sequence motifs at euchromatic loci, representing an H3K9 methylation-independent mechanism of HP1 recruitment and gene silencing.
2018-05-23 | GSE97945 | GEO
Project description:Heterochromatin formation in Schizosaccharomyces pombe requires the spreading of histone 3 (H3) Lysine 9 (K9) methylation (me) from nucleation centers by the H3K9 methylase, Suv39/Clr4, and the reader protein, HP1/Swi6. To accomplish this, Suv39/Clr4 and HP1/Swi6 have to associate with nucleosomes both nonspecifically, binding DNA and octamer surfaces and specifically, via recognition of methylated H3K9 by their respective chromodomains. However, how both proteins avoid competition for the same nucleosomes in this process is unclear. Here, we show that phosphorylation tunes the nucleosome affinity of HP1/Swi6 such that it preferentially partitions onto Suv39/Clr4’s trimethyl product rather than its unmethylated substrates. Preferential partitioning enables efficient conversion from di-to trimethylation on nucleosomes in vitro and H3K9me3 spreading in vivo. Together, our data suggests that phosphorylation of HP1/Swi6 creates a regime that relieves competition with the “read-write” mechanism of Suv39/Clr4 for productive heterochromatin spreading.
2024-12-02 | GSE271394 | GEO
Project description:H3K9 methylation (H3K9me) marks transcriptionally silent genomic regions called heterochromatin. A conserved class of HP1 proteins are critically required to establish and maintain heterochromatin. HP1 proteins bind to H3K9me, recruit factors that promote heterochromatin formation, and oligomerize to form phase-separated condensates. We do not understand how HP1 protein binding to heterochromatin establishes and maintains transcriptional silencing. Here, we demonstrate that the S.pombe HP1 homolog, Swi6, can be completely bypassed to establish silencing at ectopic and endogenous loci when an H3K4 methyltransferase, Set1 and an H3K14 acetyltransferase, Mst2 are deleted. Deleting Set1 and Mst2 enhances Clr4 enzymatic activity, leading to higher H3K9me levels and increased spreading. In contrast, Swi6 and its capacity to oligomerize were indispensable during epigenetic maintenance. Our results demonstrate the role of HP1 proteins in regulating histone modification crosstalk during establishment and identifies a genetically separable function in maintaining epigenetic memory.
2023-05-24 | GSE233333 | GEO