The Histone H4 Lysine 20 Monomethyl Mark, Set by PR-Set7 and Stabilized by L(3)mbt, Is Necessary for Proper Interphase Chromatin Organization

Ludwig-Maximilians-Universität München, Germany
PLoS ONE (Impact Factor: 3.23). 09/2012; 7(9):e45321. DOI: 10.1371/journal.pone.0045321
Source: PubMed


Drosophila PR-Set7 or SET8 is a histone methyltransferase that specifically monomethylates histone H4 lysine 20 (H4K20). L(3)MBT has been identified as a reader of methylated H4K20. It contains several conserved domains including three MBT repeats binding mono- and dimethylated H4K20 peptides. We find that the depletion of PR-Set7 blocks de novo H4K20me1 resulting in the immediate activation of the DNA damage checkpoint, an increase in the size of interphase nuclei, and drastic reduction of cell viability. L(3)mbt on the other hand stabilizes the monomethyl mark, as L(3)mbt-depleted S2 cells show a reduction of more than 60% of bulk monomethylated H4K20 (H4K20me1) while viability is barely affected. Ploidy and basic chromatin structure show only small changes in PR-Set7-depleted cells, but higher order interphase chromatin organization is significantly affected presumably resulting in the activation of the DNA damage checkpoint. In the absence of any other known functions of PR-Set7, the setting of the de novo monomethyl mark appears essential for cell viability in the presence or absence of the DNA damage checkpoint, but once newly assembled chromatin is established the monomethyl mark, protected by L(3)mbt, is dispensable.

9 Reads
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: H4K20me1 is a critical histone lysine methyl modification in eukaryotes. It is recognized and "read" by various histone lysine methyl modification binding proteins. In this study, the function of MBTD1, a member of the Polycomb protein family containing four MBT domains, was comprehensively studied in mouse oocyte meiotic maturation. The results showed that depletion of MBTD1 caused reduced expression of histone lysine methyl transferase Pr-Set7 and H4K20me1 as well as increased oocyte arrest at the GV stage. Increased γH2AX foci were formed, and DNA damage repair checkpoint protein 53BP1 was downregulated. Furthermore, depletion of MBTD1 activated the cell cycle checkpoint protein chk1 and downregulated the expression of cyclin B1 and cdc2. MBTD1 knockdown also affected chromosome configuration in GV stage oocytes and chromosome alignment at the MII stage. All these phenotypes were reproduced when the H4k20 methyl transferase Pr-Set7 was depleted. Co-IP demonstrated that MBTD1 was correlated with Pr-Set7 in mouse oocytes. Our results demonstrate that MBTD1 is associated with Pr-Set7 to stabilize H4K20me1 in mouse oocyte meiotic maturation.
    Cell cycle (Georgetown, Tex.) 03/2013; 12(7). DOI:10.4161/cc.24216 · 4.57 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Epigenetics is defined as the phenomenon of heritable phenotypic traits that are not governed by alteration of the genetic code. Major epigenetic control mechanisms include DNA methylation and post-translational modifications of histones, such as reversible histone acetylation and methylation of lysine residues. Methyllysine binding proteins recognize various levels of lysine methylation and mediate the signaling events that are induced by histone methylation. Therefore, they are also referred to as readers of the epigenetic code. In this article we review the current literature on the structure and biology of methyllysine binding proteins, especially with regard to their potential as drug targets. We also present the available inhibitors that block the interaction of methylated histones with their binding proteins.
    ChemMedChem 03/2014; 9(3). DOI:10.1002/cmdc.201300422 · 2.97 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In human cells appropriate mono-methylation of histone H4 lysine20 by PrSet7/SET8 is important for the correct transcription of specific genes, and timely progression through the cell cycle. Over-methylation appears to be prevented through the interaction of PrSet7 with PCNA, which targets PrSet7 destruction via the CRL4(cdt2) pathway, however the factors involved in positive regulation of its histone methylation remain undefined.Here we present biochemical and genetic evidence for a previously undocumented interaction between dPrSet7 and DNA polymerase-alpha in Drosophila. Depletion of the polymerase reduces H4K20 mono-methylation suggesting that it is required for the expression of dPrSet7 histone methylation activity. We also show that the interaction between PCNA and PrSet7 is conserved in Drosophila, but is only detectable in chromatin fractions. Consistent with this, S2 cells show a significant loss of chromatin bound dPrSet7 protein as S phase progresses.Based on these data we suggest that interaction with the DNA polymerase represents an important route for the expression of PrSet7 histone methylase activity, by allowing loading of dPrSet7 onto chromatin or its subsequent activation.
    Journal of Cell Science 05/2014; 127(14). DOI:10.1242/jcs.144501 · 5.43 Impact Factor
Show more

Preview (2 Sources)

9 Reads
Available from

We use cookies to give you the best possible experience on ResearchGate. Read our cookies policy to learn more.