The Lewis Lab
@peterlewislab.bsky.social
Chromatin biochemistry and genomics in development and cancer. UW-Madison School of Medicine and Public Health
TheLewisLab.net
TheLewisLab.net
VEFS: the NBD is gone. RNA binding is rare (small red bubble). Most PRC2 is RNA-free, catalytically active, and binds both CpG and non-CpG sites.
Result: diffuse H3K27me3 that dilutes PRC1 away from its normal targets, disrupting gene silencing.
Read more in our preprint: tinyurl.com/4yrwftrn
Read more in our preprint: tinyurl.com/4yrwftrn
August 13, 2025 at 9:54 PM
VEFS: the NBD is gone. RNA binding is rare (small red bubble). Most PRC2 is RNA-free, catalytically active, and binds both CpG and non-CpG sites.
Result: diffuse H3K27me3 that dilutes PRC1 away from its normal targets, disrupting gene silencing.
Read more in our preprint: tinyurl.com/4yrwftrn
Read more in our preprint: tinyurl.com/4yrwftrn
ncMUT: PRC2 still binds RNA efficiently (large red bubble, large red arrows), so catalysis stays limited. But without accessory subunits, PRC2 targeting is unfocused. Result: most PRC2 remains in the RNA-bound state, with little productive methylation at CpG islands.
August 13, 2025 at 9:54 PM
ncMUT: PRC2 still binds RNA efficiently (large red bubble, large red arrows), so catalysis stays limited. But without accessory subunits, PRC2 targeting is unfocused. Result: most PRC2 remains in the RNA-bound state, with little productive methylation at CpG islands.
Wild-type SUZ12: much of PRC2 can interact with RNA (large red bubble), which blocks engagement with nucleosomes. Accessory subunits (PRC2.1/2.2) target CpG islands. Result: strong H3K27me3 at intended sites, little elsewhere. Arrow size = rate. Bubble size = how much PRC2 is in that state.
August 13, 2025 at 9:54 PM
Wild-type SUZ12: much of PRC2 can interact with RNA (large red bubble), which blocks engagement with nucleosomes. Accessory subunits (PRC2.1/2.2) target CpG islands. Result: strong H3K27me3 at intended sites, little elsewhere. Arrow size = rate. Bubble size = how much PRC2 is in that state.
PRC2 silences genes by adding H3K27me3 at the right spots in the genome. Our model shows how the nucleic acid-binding domain (NBD) of SUZ12 keeps this activity under control, and what happens when you remove it.
August 13, 2025 at 9:54 PM
PRC2 silences genes by adding H3K27me3 at the right spots in the genome. Our model shows how the nucleic acid-binding domain (NBD) of SUZ12 keeps this activity under control, and what happens when you remove it.
VEFS: the NBD is gone. RNA binding is rare (small red bubble).
Most PRC2 is RNA-free (large green bubble), catalytically active, and binds everywhere.
Result: diffuse H3K27me3 that pulls PRC1 away from its normal targets, disrupting gene silencing.
Read more in our preprint: tinyurl.com/4yrwftrn
Result: diffuse H3K27me3 that pulls PRC1 away from its normal targets, disrupting gene silencing.
Read more in our preprint: tinyurl.com/4yrwftrn
August 13, 2025 at 9:45 PM
VEFS: the NBD is gone. RNA binding is rare (small red bubble).
Most PRC2 is RNA-free (large green bubble), catalytically active, and binds everywhere.
Result: diffuse H3K27me3 that pulls PRC1 away from its normal targets, disrupting gene silencing.
Read more in our preprint: tinyurl.com/4yrwftrn
Result: diffuse H3K27me3 that pulls PRC1 away from its normal targets, disrupting gene silencing.
Read more in our preprint: tinyurl.com/4yrwftrn
ncMUT: PRC2 still binds RNA efficiently (large red bubble, large red arrows), so catalysis stays limited.
But without accessory subunits, PRC2 targeting is unfocused.
Result:most PRC2 remains in the RNA-bound state, with little productive methylation at CpG islands.
August 13, 2025 at 9:45 PM
ncMUT: PRC2 still binds RNA efficiently (large red bubble, large red arrows), so catalysis stays limited.
But without accessory subunits, PRC2 targeting is unfocused.
Result:most PRC2 remains in the RNA-bound state, with little productive methylation at CpG islands.
Wild-type SUZ12: much of PRC2 can interact with RNA (large red bubble), which blocks engagement with nucleosomes. Accessory subunits (PRC2.1/2.2) target CpG islands.
Result: strong H3K27me3 at intended sites, little elsewhere. Arrow size = rate. Bubble size = how much PRC2 is in that state.
Result: strong H3K27me3 at intended sites, little elsewhere. Arrow size = rate. Bubble size = how much PRC2 is in that state.
August 13, 2025 at 9:45 PM
Wild-type SUZ12: much of PRC2 can interact with RNA (large red bubble), which blocks engagement with nucleosomes. Accessory subunits (PRC2.1/2.2) target CpG islands.
Result: strong H3K27me3 at intended sites, little elsewhere. Arrow size = rate. Bubble size = how much PRC2 is in that state.
Result: strong H3K27me3 at intended sites, little elsewhere. Arrow size = rate. Bubble size = how much PRC2 is in that state.
Our results support a model where SUZ12-NBD interactions with RNA act as a kinetic buffer, limiting PRC2 activity and ensuring specific targeting to CpG islands. Loss of the NBD (VEFS) disrupts this equilibrium, driving widespread, non-specific H3K27me3 deposition. 13/13
July 23, 2025 at 11:38 PM
Our results support a model where SUZ12-NBD interactions with RNA act as a kinetic buffer, limiting PRC2 activity and ensuring specific targeting to CpG islands. Loss of the NBD (VEFS) disrupts this equilibrium, driving widespread, non-specific H3K27me3 deposition. 13/13
PRC2 complexes containing the SUZ12-NBD strongly bind diverse forms of nucleic acids, including structured RNA and double-stranded DNA, significantly inhibiting enzymatic activity. PRC2 lacking the NBD (VEFS) is resistant to nucleic acid-mediated inhibition. 12/13
July 23, 2025 at 11:38 PM
PRC2 complexes containing the SUZ12-NBD strongly bind diverse forms of nucleic acids, including structured RNA and double-stranded DNA, significantly inhibiting enzymatic activity. PRC2 lacking the NBD (VEFS) is resistant to nucleic acid-mediated inhibition. 12/13
Domain analysis identifies a discrete nucleic acid-binding domain (NBD) within SUZ12 responsible for constraining PRC2 activity. CryoEM studies showed the NBD in close proximity to nucleic acids. Loss of this region (NEC, VEFS) causes global H3K27me3 hypermethylation. 11/13
July 23, 2025 at 11:38 PM
Domain analysis identifies a discrete nucleic acid-binding domain (NBD) within SUZ12 responsible for constraining PRC2 activity. CryoEM studies showed the NBD in close proximity to nucleic acids. Loss of this region (NEC, VEFS) causes global H3K27me3 hypermethylation. 11/13
Widespread, diffuse H3K27me3 deposition induced by VEFS expression titrates canonical PRC1 away from key genomic targets. This dispersal of PRC1 disrupts Polycomb domains, resulting in transcriptional derepression and upregulation of genes normally silenced by PRC1. 10/13
July 23, 2025 at 11:38 PM
Widespread, diffuse H3K27me3 deposition induced by VEFS expression titrates canonical PRC1 away from key genomic targets. This dispersal of PRC1 disrupts Polycomb domains, resulting in transcriptional derepression and upregulation of genes normally silenced by PRC1. 10/13
Expression of the VEFS truncation globally elevates H3K27me3 independently of non-core accessory subunits. This increase occurs across multiple cell types, including both K27M-mutant DMG cells and wild-type H3 cells, highlighting intrinsic SUZ12 regulatory mechanisms. 9/13
July 23, 2025 at 11:38 PM
Expression of the VEFS truncation globally elevates H3K27me3 independently of non-core accessory subunits. This increase occurs across multiple cell types, including both K27M-mutant DMG cells and wild-type H3 cells, highlighting intrinsic SUZ12 regulatory mechanisms. 9/13
In vitro and in vivo data confirm PRC2 subcomplexes collectively support K27M-DMG proliferation. Disrupting PRC2 recruitment (ncMUT, VEFS) dramatically reduces tumor growth, and remarkably, VEFS expression alone leads to 100% survival in orthotopic xenograft models. 8/13
July 23, 2025 at 11:38 PM
In vitro and in vivo data confirm PRC2 subcomplexes collectively support K27M-DMG proliferation. Disrupting PRC2 recruitment (ncMUT, VEFS) dramatically reduces tumor growth, and remarkably, VEFS expression alone leads to 100% survival in orthotopic xenograft models. 8/13
EZH2 inhibition (Tazemetostat) or disruption of PRC2 subcomplexes (shSUZ12, ncMUT, VEFS) derepresses CDKN2A, causing significant growth defects. Knockout of CDKN2A rescues DMG cells from these proliferation defects, highlighting its critical role downstream of PRC2. 7/13
July 23, 2025 at 11:38 PM
EZH2 inhibition (Tazemetostat) or disruption of PRC2 subcomplexes (shSUZ12, ncMUT, VEFS) derepresses CDKN2A, causing significant growth defects. Knockout of CDKN2A rescues DMG cells from these proliferation defects, highlighting its critical role downstream of PRC2. 7/13
RNA-seq data show that disrupting PRC2 subcomplexes (ncMUT, VEFS) in DMG cells significantly derepresses genes critical for neurodevelopment. PRC2.1/2.2 complexes thus maintain silencing of developmental regulators essential for tumor cell identity. 6/13
July 23, 2025 at 11:38 PM
RNA-seq data show that disrupting PRC2 subcomplexes (ncMUT, VEFS) in DMG cells significantly derepresses genes critical for neurodevelopment. PRC2.1/2.2 complexes thus maintain silencing of developmental regulators essential for tumor cell identity. 6/13
ChIP-seq analyses reveal PRC2.1 and PRC2.2 subcomplexes act collectively to recruit PRC2 to critical genomic loci in K27M DMGs. Mutants lacking these accessory subunits (ncMUT, VEFS) show severely impaired PRC2 localization at key target genes, including CDKN2A. 5/13
July 23, 2025 at 11:38 PM
ChIP-seq analyses reveal PRC2.1 and PRC2.2 subcomplexes act collectively to recruit PRC2 to critical genomic loci in K27M DMGs. Mutants lacking these accessory subunits (ncMUT, VEFS) show severely impaired PRC2 localization at key target genes, including CDKN2A. 5/13
To investigate PRC2 targeting, we disrupted PRC2 subcomplexes using SUZ12 mutants. VEFS truncation removes all accessory subunits, while the non-core mutant (ncMUT) selectively disrupts PRC2.1 and PRC2.2 subcomplexes, preserving core PRC2 integrity. 4/13
July 23, 2025 at 11:38 PM
To investigate PRC2 targeting, we disrupted PRC2 subcomplexes using SUZ12 mutants. VEFS truncation removes all accessory subunits, while the non-core mutant (ncMUT) selectively disrupts PRC2.1 and PRC2.2 subcomplexes, preserving core PRC2 integrity. 4/13
Recent studies show non-core (accessory) subunits are necessary for PRC2 targeting in mammalian cells. These subunits, interacting via SUZ12, guide PRC2 precisely to CpG islands, ensuring accurate H3K27me3 deposition and gene silencing. 3/13
July 23, 2025 at 11:38 PM
Recent studies show non-core (accessory) subunits are necessary for PRC2 targeting in mammalian cells. These subunits, interacting via SUZ12, guide PRC2 precisely to CpG islands, ensuring accurate H3K27me3 deposition and gene silencing. 3/13
Diffuse midline gliomas (DMGs) carrying the H3 K27M inhibitor histone exhibit global H3K27me3 reduction but retain focal enrichment at PRC2-bound CpG islands. Understanding how this residual methylation is maintained and its functional role is a critical unresolved question. 2/13
July 23, 2025 at 11:38 PM
Diffuse midline gliomas (DMGs) carrying the H3 K27M inhibitor histone exhibit global H3K27me3 reduction but retain focal enrichment at PRC2-bound CpG islands. Understanding how this residual methylation is maintained and its functional role is a critical unresolved question. 2/13
We are excited to share our new preprint demonstrating that nucleic acid interactions with SUZ12 constrain PRC2 activity, establishing a kinetic buffer essential for targeted gene silencing and revealing vulnerabilities in diffuse midline gliomas.
www.biorxiv.org/content/10.1...
www.biorxiv.org/content/10.1...
July 23, 2025 at 11:38 PM
We are excited to share our new preprint demonstrating that nucleic acid interactions with SUZ12 constrain PRC2 activity, establishing a kinetic buffer essential for targeted gene silencing and revealing vulnerabilities in diffuse midline gliomas.
www.biorxiv.org/content/10.1...
www.biorxiv.org/content/10.1...
Domain analysis identifies a discrete nucleic acid-binding domain (NBD) within the SUZ12 N-terminus responsible for constraining PRC2 activity. CryoEM studies previously showed the NBD in close proximity to nucleic acids. Loss of this region (NEC, VEFS) causes global H3K27me3 hypermethylation. 11/13
July 23, 2025 at 11:01 PM
Domain analysis identifies a discrete nucleic acid-binding domain (NBD) within the SUZ12 N-terminus responsible for constraining PRC2 activity. CryoEM studies previously showed the NBD in close proximity to nucleic acids. Loss of this region (NEC, VEFS) causes global H3K27me3 hypermethylation. 11/13
Widespread, diffuse H3K27me3 deposition induced by VEFS expression titrates canonical PRC1 away from key genomic targets. This dispersal of PRC1 disrupts Polycomb domains, resulting in transcriptional derepression and upregulation of genes normally silenced by PRC1. 10/13
July 23, 2025 at 11:01 PM
Widespread, diffuse H3K27me3 deposition induced by VEFS expression titrates canonical PRC1 away from key genomic targets. This dispersal of PRC1 disrupts Polycomb domains, resulting in transcriptional derepression and upregulation of genes normally silenced by PRC1. 10/13
Expression of the VEFS truncation globally elevates H3K27me3 independently of non-core accessory subunits. This substantial increase occurs across multiple cell types, including both K27M-mutant DMG cells and wild-type H3 cells, highlighting intrinsic SUZ12 regulatory mechanisms. 9/13
July 23, 2025 at 11:01 PM
Expression of the VEFS truncation globally elevates H3K27me3 independently of non-core accessory subunits. This substantial increase occurs across multiple cell types, including both K27M-mutant DMG cells and wild-type H3 cells, highlighting intrinsic SUZ12 regulatory mechanisms. 9/13
In vitro and in vivo data confirm PRC2 subcomplexes collectively support K27M-DMG proliferation. Disrupting PRC2 recruitment (ncMUT, VEFS) dramatically reduces tumor growth, and remarkably, VEFS expression alone leads to 100% survival in orthotopic xenograft models. 8/13
July 23, 2025 at 11:01 PM
In vitro and in vivo data confirm PRC2 subcomplexes collectively support K27M-DMG proliferation. Disrupting PRC2 recruitment (ncMUT, VEFS) dramatically reduces tumor growth, and remarkably, VEFS expression alone leads to 100% survival in orthotopic xenograft models. 8/13
EZH2 inhibition (Tazemetostat) or disruption of PRC2 subcomplexes (shSUZ12, ncMUT, VEFS) derepresses CDKN2A, causing significant growth defects. Knockout of CDKN2A rescues DMG cells from these proliferation defects, highlighting its critical role downstream of PRC2. 7/13
July 23, 2025 at 11:01 PM
EZH2 inhibition (Tazemetostat) or disruption of PRC2 subcomplexes (shSUZ12, ncMUT, VEFS) derepresses CDKN2A, causing significant growth defects. Knockout of CDKN2A rescues DMG cells from these proliferation defects, highlighting its critical role downstream of PRC2. 7/13