Dataset Information

SUZ12 immunoprecipitation followed by protein indentification via mass spectrometry (SUZ12 IP-MS) in mESCs of SUZ12 WT, delta exon 4, KO, and KO rescues with SUZ12-L and SUZ12-S

ABSTRACT: Suz12 exon 4 encodes 23 amino acids (aa 129–152 in SUZ12-L) that partially overlap with the WD-binding domain 1 (WDB1, 110–145). We reasoned that exon 4 skipping might alter the structure of SUZ12 and, possibly, PRC2 composition. To explore this possibility, we generated ESCs that lack the Suz12 exon 4 via CRISPR-Cas9–induced deletion. In addition, to rule out any biases due to the expression levels and/or SUZ12 epitope masking, we generated Suz12 knockout (KO) ESCs (herein, KO) in which Suz12 expression was subsequently rescued by re-introducing either the Suz12-L or Suz12-S mouse isoform fused to a triple-Flag tag under the regulation of a CAG promoter (KO+L/S; Figures S2H–S2K). We performed SUZ12 immunoprecipitation coupled with mass spectrometry (IP-MS) in the WT and ∆ex4 clones to compare their interactomes and with a flag antibody in the KO and rescue cell lines. As expected, no peptides corresponding to exon 4 were retrieved in ∆ex4 samples, while the rest of the sequence displayed similar coverage. Comparison of interactors in the two conditions revealed that SUZ12 binding to AEBP2 and JARID2 was strongly reduced in ∆ex4 cells with respect to WT cells, whereas SUZ12 binding to most core components or to PRC2.1-specific factors was unchanged or only slightly increased . These observations were confirmed by SUZ12 IP followed by Western blot (WB). Flag IP-MS in rescue cells confirmed that, while the long isoform was able to correctly form comparable amounts of both PRC2.1 and PRC2.2 subtypes, interaction of the SUZ12-S with PRC2.2-specific factors was drastically reduced.

INSTRUMENT(S): LTQ Orbitrap Velos Pro

ORGANISM(S): Mus Musculus (mouse)

TISSUE(S): Stem Cell

SUBMITTER: Niccolò Arecco

LAB HEAD: Niccolò Arecco

PROVIDER: PXD046660 | Pride | 2024-03-18

REPOSITORIES: Pride

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Publications

Alternative splicing decouples local from global PRC2 activity.

Arecco Niccolò N Mocavini Ivano I Blanco Enrique E Ballaré Cecilia C Libman Elina E Bonnal Sophie S Irimia Manuel M Di Croce Luciano L

Molecular cell 20240306 6

The Polycomb repressive complex 2 (PRC2) mediates epigenetic maintenance of gene silencing in eukaryotes via methylation of histone H3 at lysine 27 (H3K27). Accessory factors define two distinct subtypes, PRC2.1 and PRC2.2, with different actions and chromatin-targeting mechanisms. The mechanisms orchestrating PRC2 assembly are not fully understood. Here, we report that alternative splicing (AS) of PRC2 core component SUZ12 generates an uncharacterized isoform SUZ12-S, which co-exists with the c ...[more]

PMID: 38452766

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Project description:Whole genome profiling of 4 histone modifications (H3K27me1, H3K27me3,H3K36me1 and H3K36me3) using ChIP-on-chip. It has recently been shown that nucleosome distribution, histone modifications and RNA polymerase II (Pol II) occupancy show preferential association with exons ("exon-intron marking"), linking chromatin structure and function to co- transcriptional splicing in a variety of eukaryotes. Previous ChIP-sequencing studies suggested that these marking patterns reflect the nucleosomal landscape. By analyzing ChIP-chip datasets across the human genome in three cell types, we have found that this marking system is far more complex than previously observed. We show here that a range of histone modifications and Pol II are preferentially associated with exons. However, there is noticeable cell-type specificity in the degree of exon marking by histone modifications and, surprisingly, this is also reflected in some histone modifications patterns showing biases towards introns. Exon-intron marking is laid down in the absence of transcription on silent genes, with some marking biases changing or becoming reversed for genes expressed at different levels. Furthermore, the relationship of this marking system with splicing is not simple, with only some histone modifications reflecting exon usage/inclusion, while others mirror patterns of exon exclusion. By examining nucleosomal distributions in all three cell types, we demonstrate that these histone modification patterns cannot solely be accounted for by differences in nucleosome levels between exons and introns. In addition, because of inherent differences between ChIP-chip array and ChIP-sequencing approaches, these platforms report different nucleosome distribution patterns across the human genome. Our findings confound existing views and point to active cellular mechanisms which dynamically regulate histone modification levels and account for exon-intron marking. We believe that these histone modification patterns provide links between chromatin accessibility, Pol II movement and co-transcriptional splicing.

Dataset Information

SUZ12 immunoprecipitation followed by protein indentification via mass spectrometry (SUZ12 IP-MS) in mESCs of SUZ12 WT, delta exon 4, KO, and KO rescues with SUZ12-L and SUZ12-S

Publications

Alternative splicing decouples local from global PRC2 activity.

Similar Datasets

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