Review
Plant Sciences
Lea Faivre, Daniel Schubert
Summary: Chromatin is important for transcriptional regulation, and the histone modifications H3K4me3 and H3K27me3 are usually described as mutually exclusive activator and repressor. However, recent studies show that these marks can co-exist, forming a distinctive chromatin state called bivalency. The role of bivalency in transcriptional regulation remains unclear, but it is proposed to maintain transcriptional plasticity and prevent irreversible silencing of target genes. This review explores the potential factors involved in bivalency and highlights techniques for further study.
JOURNAL OF EXPERIMENTAL BOTANY
(2023)
Article
Biology
Maksim Erokhin, Fedor Gorbenko, Dmitry Lomaev, Marina Yu Mazina, Anna Mikhailova, Azat K. Garaev, Aleksander Parshikov, Nadezhda E. Vorobyeva, Pavel Georgiev, Paul Schedl, Darya Chetverina
Summary: This study demonstrates that the repressing activity of PREs can be induced or enhanced by nearby boundary elements in Drosophila, suggesting a potential mechanism for altering chromatin structure to enable access to critical factors for PcG silencing.
Review
Entomology
Jean-Michel Gibert, Frederique Peronnet
Summary: Drosophila melanogaster has played a crucial role in epigenetics, studying changes in gene function inherited through mitosis or meiosis that are not due to changes in the DNA sequence. By analyzing simple phenotypes, such as bristle position or cuticle pigmentation, identification of mutated genes led to the discovery of major chromatin regulators that are often conserved in distantly related organisms.
Article
Oncology
Reza Ghasemi, Heidi Struthers, Elisabeth R. Wilson, David H. Spencer
Summary: Transcriptional regulation of HOXA genes in AML cells with the NPM1c mutation involves CTCF-mediated chromatin loops and the opposing actions of the COMPASS and Polycomb epigenetic complexes. Deleting CTCF binding sites in AML cells reduces long-range interactions, but HOXA gene expression can still be sustained through interactions with SKAP2 enhancers or intrinsic factors within the gene cluster.
Review
Cell Biology
Joyce Taylor-Papadimitriou, Joy M. Burchell
Summary: This review focuses on the role of PcG and TrxG complexes in the epigenetic regulation of gene expression and discusses the regulation of suppressive and active marks by methylases and demethylases. Mutations in histone methylases and demethylases in cancer can lead to repression of genes or activation of oncogenes.
Article
Biochemistry & Molecular Biology
Bhavana Kayyar, Anjhana C. Ravikkumar, Utsa Bhaduri, M. R. S. Rao
Summary: Sox8 is a crucial transcription factor that plays an important role in sex maintenance and fertility of adult mice. It is regulated by the lncRNA Mrhl in a p68-dependent manner under the control of the Wnt signaling pathway. The downregulation of Mrhl leads to the meiotic commitment of the spermatogonial cells through Sox8 dependence. The involvement of architectural proteins CTCF and cohesin in mediating a chromatin loop, as well as the interaction between lncRNA Mrhl and the Sox8 locus through a DNA:DNA:RNA triplex, are important for the regulation of Sox8 expression.
MOLECULAR AND CELLULAR BIOLOGY
(2022)
Article
Cell Biology
Najma Shaheen, Jawad Akhtar, Zain Umer, Muhammad Haider Farooq Khan, Mahnoor Hussain Bakhtiari, Murtaza Saleem, Amir Faisal, Muhammad Tariq
Summary: This study uncovers an interaction between Polycomb and CCT7 in Drosophila, showing that CCT7 plays a role in maintaining PcG gene repression. The findings support a strong genetic interaction between Pc and CCT7 mutants, and suggest that CCT7 is an important modulator of Pc recruitment at chromatin.
FRONTIERS IN CELL AND DEVELOPMENTAL BIOLOGY
(2021)
Article
Biochemistry & Molecular Biology
Xingcheng Lin, Rachel Leicher, Shixin Liu, Bin Zhang
Summary: This study utilized various techniques to elucidate the structure of Polycomb repressive complex 2 (PRC2) and its interactions with DNA, confirming that PRC2 binds to DNA in multiple ways, forming a loop-like configuration.
NUCLEIC ACIDS RESEARCH
(2021)
Article
Multidisciplinary Sciences
Kenneth Wu, Namrita Dhillon, Kelvin Du, Rohinton T. Kamakaka
Summary: Gene silencing in budding yeast is maintained by unacetylated nucleosomes and requires 50% to 75% acetylation for activation. The Sir4 gene is a key component in maintaining gene silencing, with even a two-fold reduction in acetyltransferases potentially leading to transcriptional silence.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Biology
Graham J. M. Hickey, Candice L. Wike, Xichen Nie, Yixuan Guo, Mengyao Tan, Patrick J. Murphy, Bradley R. Cairns
Summary: This study reveals the order and mechanism of establishing developmental gene poising in zebrafish embryos, highlighting the critical role of H2Aub1.
Article
Cell Biology
Nadezda A. Fursova, Anne H. Turberfield, Neil P. Blackledge, Emma L. Findlater, Anna Lastuvkova, Miles K. Huseyin, Paula Dobrinic, Robert J. Klose
Summary: Histone modifications play crucial roles in gene regulation and development, with little known about modifications found broadly throughout the genome. BAP1 deubiquitylase constrains H2AK119ub1 accumulation throughout the genome, impacting gene expression and transcription. Failure to constrain H2AK119ub1 compromises Polycomb complex occupancy at certain target genes, resulting in their derepression.
GENES & DEVELOPMENT
(2021)
Article
Biology
Sarah Lensch, Michael H. Herschl, Connor H. Ludwig, Joydeb Sinha, Michaela M. Hinks, Adi Mukund, Taihei Fujimori, Lacramioara Bintu
Summary: This study systematically investigates gene coupling in mammalian cells and finds that gene silencing and reactivation can act at a distance, involving histone modification and chromatin regulator recruitment. The configuration of insulator elements also plays a role in this process.
Article
Biochemistry & Molecular Biology
Darya Chetverina, Nadezhda E. Vorobyeva, Marina Yu Mazina, Lika Fab, Dmitry Lomaev, Alexandra Golovnina, Vladic Mogila, Pavel Georgiev, Rustam H. Ziganshin, Maksim Erokhin
Summary: The Polycomb group (PcG) and Trithorax group (TrxG) proteins are key epigenetic regulators controlling gene expression in multicellular organisms. This study investigates the recruitment and interactions of PRE DNA-binding proteins in Drosophila. The results suggest that Combgap, Zeste, Psq, and Adf1 have associations with different protein complexes involved in regulatory activities, indicating their potential multifunctional role in transcription regulation.
CELLULAR AND MOLECULAR LIFE SCIENCES
(2022)
Article
Biology
Sean Akira Montgomery, Tetsuya Hisanaga, Nan Wang, Elin Axelsson, Svetlana Akimcheva, Milos Sramek, Chang Liu, Frederic Berger
Summary: This study investigates gene dosage control in the short-lived diploid embryo of the plant Marchantia polymorpha. It reveals that paternal chromosomes are repressed throughout embryogenesis, resulting in functional haploidy. The findings demonstrate the importance of maintaining haploid gene dosage through genomic imprinting during embryonic development.
Review
Plant Sciences
Dong-Hwan Kim
Summary: Polycomb repressive complexes (PRCs) are crucial for the growth and development of eukaryotes, with conserved components among most eukaryotes. The study of PRCs' gene silencing in plants has contributed to the understanding of the epigenetic control of developmental programs. This review provides current knowledge on PcG-mediated gene regulation, focusing on its role in various aspects of plant development and the molecular mechanisms involved, specifically in Arabidopsis plants.
JOURNAL OF PLANT BIOLOGY
(2023)