scholarly journals EZHIP constrains Polycomb Repressive Complex 2 activity in germ cells

2019 ◽  
Author(s):  
R Ragazzini ◽  
R Pérez-Palacios ◽  
HI Baymaz ◽  
S Diop ◽  
K Ancelin ◽  
...  
Keyword(s):  
Chromatin Remodeling ◽  
Critical Role ◽  
Core Complex ◽  
Polycomb Repressive Complex ◽  
Inhibitory Protein ◽  
Polycomb Repressive Complex 2 ◽  
The Core ◽  
Accessory Subunits ◽  
Global Increase ◽  
Late Stages

ABSTRACTThe Polycomb machinery is required for the proper orchestration of gene expression by virtue of its critical role in maintaining transcriptional silencing. It is composed of several chromatin modifying complexes, including Polycomb Repressive Complex 2 (PRC2), which deposits H3K27me2/3. Here, we report the identification of a new cofactor of PRC2, EZHIP (EZH1/2 Inhibitory Protein), expressed predominantly in the gonads. EZHIP limits the enzymatic activity of PRC2 and lessens the interaction between the core complex and its accessory subunits, but does not interfere with PRC2 recruitment to chromatin. Deletion ofEzhipleads to a global increase in H3K27me2/3 deposition both during spermatogenesis and at late stages of oocyte maturation. This alteration of the epigenetic content of mature oocytes does not affect the initial number of follicles but is associated with a reduction of follicles in aging mice. We provide evidences that mature oocytesEzhip-/- are not fully functional and that fertility is strongly impaired inEzhip-/- females. Altogether, our study uncovers EZHIP as a novel functional player in the comprehensive chromatin remodeling that occurs in the gonads.

scholarly journals EZHIP constrains Polycomb Repressive Complex 2 activity in germ cells

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Roberta Ragazzini ◽  
Raquel Pérez-Palacios ◽  
Irem H. Baymaz ◽  
Seynabou Diop ◽  
Katia Ancelin ◽  
...  
Keyword(s):  
Polycomb Group ◽  
Initial Number ◽  
Core Complex ◽  
Polycomb Repressive Complex ◽  
Inhibitory Protein ◽  
Polycomb Repressive Complex 2 ◽  
The Core ◽  
Accessory Subunits ◽  
Global Increase ◽  
Late Stages

Abstract The Polycomb group of proteins is required for the proper orchestration of gene expression due to its role in maintaining transcriptional silencing. It is composed of several chromatin modifying complexes, including Polycomb Repressive Complex 2 (PRC2), which deposits H3K27me2/3. Here, we report the identification of a cofactor of PRC2, EZHIP (EZH1/2 Inhibitory Protein), expressed predominantly in the gonads. EZHIP limits the enzymatic activity of PRC2 and lessens the interaction between the core complex and its accessory subunits, but does not interfere with PRC2 recruitment to chromatin. Deletion of Ezhip in mice leads to a global increase in H3K27me2/3 deposition both during spermatogenesis and at late stages of oocyte maturation. This does not affect the initial number of follicles but is associated with a reduction of follicles in aging. Our results suggest that mature oocytes Ezhip−/− might not be fully functional and indicate that fertility is strongly impaired in Ezhip−/− females. Altogether, our study uncovers EZHIP as a regulator of chromatin landscape in gametes.

scholarly journals Baculovirus Per Os Infectivity Factor Complex: Components and Assembly

2019 ◽  
Vol 93 (6) ◽  
Author(s):  
Xi Wang ◽  
Yu Shang ◽  
Cheng Chen ◽  
Shurui Liu ◽  
Meng Chang ◽  
...  
Keyword(s):  
Polyacrylamide Gel Electrophoresis ◽  
Critical Role ◽  
Previous Knowledge ◽  
Multiprotein Complex ◽  
Core Complex ◽  
Insect Midgut ◽  
Content Type ◽  
The Core ◽  
Liquid Chromatography Tandem Mass ◽  
The Impact

ABSTRACT Baculovirus entry into insect midgut cells is dependent on a multiprotein complex of per os infectivity factors (PIFs) on the envelopes of occlusion-derived virions (ODVs). The structure and assembly of the PIF complex are largely unknown. To reveal the complete members of the complex, a combination of blue native polyacrylamide gel electrophoresis, liquid chromatography-tandem mass spectrometry, and Western blotting was conducted on three different baculoviruses. The results showed that the PIF complex has a molecular mass of ∼500 kDa and consists of nine PIFs, including a newly discovered member (PIF9). To decipher the assembly process, each pif gene was knocked out from the Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV) genome individually by use of synthetic baculovirus technology, and the impact on PIF complex formation was investigated. Deletion of pif8 resulted in the formation of an ∼400-kDa subcomplex. Deletion of pif0, -4, -6, -7, or -9 resulted in a subcomplex of ∼230 kDa, but deletion of pif1, -2, or -3 abolished formation of any complex. Taken together, our data identified a core complex of ∼230 kDa, consisting of PIF1, -2, and -3. This revised the previous knowledge that the core complex was about 170 kDa and contained PIF1 to -4. Analysis of the PIF complex in cellular fractions suggested that it is assembled in the cytoplasm before being transported to the nucleus and subsequently incorporated into the envelopes of ODVs. Only the full complex, not the subcomplex, is resistant to proteolytic attack, indicating the essentiality of correct complex assembly for oral infection. IMPORTANCE Entry of baculovirus into host insects is mediated by a per os infectivity factor (PIF) complex on the envelopes of occlusion-derived viruses (ODVs). Knowledge of the composition and structure of the PIF complex is fundamental to understanding its mode of action. By using multiple approaches, we determined the complete list of proteins (nine) in the PIF complex. In contrast to previous knowledge in the field, the core complex is revised to ∼230 kDa and consists of PIF1 to -3 but not PIF4. Interestingly, our results suggest that the PIF complex is formed in the cytoplasm prior to its transport to the nucleus and subsequent incorporation into ODVs. Only the full complex is resistant to proteolytic degradation in the insect midgut, implying the critical role of the entire complex. These findings provide the baseline for future studies on the ODV entry mechanism mediated by the multiprotein complex.

scholarly journals Single-molecule and in silico dissection of the interaction between Polycomb repressive complex 2 and chromatin

2020 ◽  
Vol 117 (48) ◽  
pp. 30465-30475
Author(s):  
Rachel Leicher ◽  
Eva J. Ge ◽  
Xingcheng Lin ◽  
Matthew J. Reynolds ◽  
Wenjun Xie ◽  
...  
Keyword(s):  
Single Molecule ◽  
Polycomb Group ◽  
Chromatin Interaction ◽  
Binding Modes ◽  
Polycomb Repressive Complex ◽  
Single Molecule Force Spectroscopy ◽  
Polycomb Repressive Complex 2 ◽  
Major Interest ◽  
Accessory Subunits ◽  
Dynamics Simulations

Polycomb repressive complex 2 (PRC2) installs and spreads repressive histone methylation marks on eukaryotic chromosomes. Because of the key roles that PRC2 plays in development and disease, how this epigenetic machinery interacts with DNA and nucleosomes is of major interest. Nonetheless, the mechanism by which PRC2 engages with native-like chromatin remains incompletely understood. In this work, we employ single-molecule force spectroscopy and molecular dynamics simulations to dissect the behavior of PRC2 on polynucleosome arrays. Our results reveal an unexpectedly diverse repertoire of PRC2 binding configurations on chromatin. Besides reproducing known binding modes in which PRC2 interacts with bare DNA, mononucleosomes, and adjacent nucleosome pairs, our data also provide direct evidence that PRC2 can bridge pairs of distal nucleosomes. In particular, the “1–3” bridging mode, in which PRC2 engages two nucleosomes separated by one spacer nucleosome, is a preferred low-energy configuration. Moreover, we show that the distribution and stability of different PRC2–chromatin interaction modes are modulated by accessory subunits, oncogenic histone mutations, and the methylation state of chromatin. Overall, these findings have implications for the mechanism by which PRC2 spreads histone modifications and compacts chromatin. The experimental and computational platforms developed here provide a framework for understanding the molecular basis of epigenetic maintenance mediated by Polycomb-group proteins.

scholarly journals Two Subunits Specific to the PBAP Chromatin Remodeling Complex Have Distinct and Redundant Functions during Drosophila Development

2008 ◽  
Vol 28 (17) ◽  
pp. 5238-5250 ◽  
Author(s):  
Inés Carrera ◽  
Jiri Zavadil ◽  
Jessica E. Treisman
Keyword(s):  
Chromatin Remodeling ◽  
Germ Line ◽  
Ovarian Follicle ◽  
Follicle Cells ◽  
Mutant Form ◽  
The Core ◽  
Dna Binding Sites ◽  
Accessory Subunits ◽  
Chromatin Remodeling Complexes ◽  
Brahma Complex

ABSTRACT Chromatin remodeling complexes control the availability of DNA binding sites to transcriptional regulators. Two distinct conserved forms of the SWI/SNF class of complexes are characterized by the presence of specific accessory subunits. In Drosophila, the core Brahma complex associates either with Osa to form the BAP complex or with Bap170 and Bap180 to form the PBAP complex. osa mutations reproduce only a subset of the developmental phenotypes caused by mutations in subunits of the core complex. To test whether the PBAP complex performs the remaining functions, we generated mutations in bap170 and bap180. Surprisingly, we found that Bap180 is not essential for viability, although it is required in ovarian follicle cells for normal eggshell development. Bap170 is necessary to stabilize the Bap180 protein, but a mutant form that retains this function is sufficient for both survival and fertility. The two subunits act redundantly to allow metamorphosis; using gene expression profiling of bap170 bap180 double mutants, we found that the PBAP complex regulates genes involved in tissue remodeling and immune system function. Finally, we generated mutants lacking Bap170, Bap180, and Osa in the germ line to demonstrate that the core Brahma complex can function in oogenesis without any of these accessory subunits.

scholarly journals Correction to: ZFP281 recruits polycomb repressive complex 2 to restrict extraembryonic endoderm potential in safeguarding embryonic stem cell pluripotency

2021 ◽  
Author(s):  
Xin Huang ◽  
Nazym Bashkenova ◽  
Jihong Yang ◽  
Dan Li ◽  
Jianlong Wang
Keyword(s):  
Stem Cell ◽  
Embryonic Stem Cell ◽  
Embryonic Stem ◽  
Original Publication ◽  
Polycomb Repressive Complex ◽  
Polycomb Repressive Complex 2 ◽  
Extraembryonic Endoderm ◽  
Stem Cell Pluripotency ◽  
Embryonic Stem Cell Pluripotency

In the original publication the labelling in middle and bottom panels of figure 2k is published incorrectly as “Soc17”. The correct labeling is available in this correction as “Sox17”.

scholarly journals The epigenetic regulator LSH maintains fork protection and genomic stability via MacroH2A deposition and RAD51 filament formation

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xiaoping Xu ◽  
Kai Ni ◽  
Yafeng He ◽  
Jianke Ren ◽  
Chongkui Sun ◽  
...  
Keyword(s):  
Chromatin Remodeling ◽  
Critical Role ◽  
Genomic Stability ◽  
Dna Degradation ◽  
Replication Forks ◽  
Filament Formation ◽  
Epigenetic Regulator ◽  
Centromeric Instability ◽  
Stalled Replication Forks

AbstractThe Immunodeficiency Centromeric Instability Facial Anomalies (ICF) 4 syndrome is caused by mutations in LSH/HELLS, a chromatin remodeler promoting incorporation of histone variant macroH2A. Here, we demonstrate that LSH depletion results in degradation of nascent DNA at stalled replication forks and the generation of genomic instability. The protection of stalled forks is mediated by macroH2A, whose knockdown mimics LSH depletion and whose overexpression rescues nascent DNA degradation. LSH or macroH2A deficiency leads to an impairment of RAD51 loading, a factor that prevents MRE11 and EXO1 mediated nascent DNA degradation. The defect in RAD51 loading is linked to a disbalance of BRCA1 and 53BP1 accumulation at stalled forks. This is associated with perturbed histone modifications, including abnormal H4K20 methylation that is critical for BRCA1 enrichment and 53BP1 exclusion. Altogether, our results illuminate the mechanism underlying a human syndrome and reveal a critical role of LSH mediated chromatin remodeling in genomic stability.

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