Polycomb Group (PcG) histone-modifying system is key in maintaining gene repression, providing a mitotically heritable cellular memory. Nevertheless, to allow plants to transition through distinct transcriptional programs during development or to respond to external cues, PcG-mediated repression requires reversibility. Several data suggest that the dynamics of PcG marks may vary considerably in different cell contexts; however, how PcG marks are established, maintained, or removed in each case is far from clear. In this review, we survey the knowns and unknowns of the molecular mechanisms underlying the maintenance or turnover of PcG marks in different cell stages.
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http://dx.doi.org/10.1016/j.pbi.2024.102553 | DOI Listing |
Genome Biol
January 2025
Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, Centre National de La Recherche Scientifique (CNRS), Commissariat À L'EnergieAtomique (CEA), Gif-Sur-Yvette, 91190, France.
Background: The DNA/H3K9 methylation and Polycomb-group proteins (PcG)-H3K27me3 silencing pathways have long been considered mutually exclusive and specific to transposable elements (TEs) and genes, respectively in mammals, plants, and fungi. However, H3K27me3 can be recruited to many TEs in the absence of DNA/H3K9 methylation machinery and sometimes also co-occur with DNA methylation.
Results: In this study, we show that TEs can also be solely targeted and silenced by H3K27me3 in wild-type Arabidopsis plants.
Mol Cells
December 2024
Department of Systems Biology, Yonsei University, Seoul 03722, Republic of Korea. Electronic address:
Polycomb group (PcG) proteins play key roles in development by repressing thousands of targets through histone modifications. However, how PcG is recruited to specific targets is poorly understood. In Arabidopsis, certain noncoding RNAs are necessary for recruiting the PcG protein CURLY LEAF (CLF) to its target sites.
View Article and Find Full Text PDFEpigenetics Chromatin
May 2024
Center for Molecular and Cellular Biology, Skolkovo Institute of Science and Technology, Bolshoy Boulevard 30, Build.1, Moscow, 121205, Russia.
The three-dimensional organization of the genome plays a central role in the regulation of cellular functions, particularly in the human brain. This review explores the intricacies of chromatin organization, highlighting the distinct structural patterns observed between neuronal and non-neuronal brain cells. We integrate findings from recent studies to elucidate the characteristics of various levels of chromatin organization, from differential compartmentalization and topologically associating domains (TADs) to chromatin loop formation.
View Article and Find Full Text PDFCurr Opin Plant Biol
August 2024
Institute of Plant Biochemistry and Photosynthesis (IBVF-CSIC-US), Avenida Américo Vespucio 49, 41092, Seville, Spain. Electronic address:
Polycomb Group (PcG) histone-modifying system is key in maintaining gene repression, providing a mitotically heritable cellular memory. Nevertheless, to allow plants to transition through distinct transcriptional programs during development or to respond to external cues, PcG-mediated repression requires reversibility. Several data suggest that the dynamics of PcG marks may vary considerably in different cell contexts; however, how PcG marks are established, maintained, or removed in each case is far from clear.
View Article and Find Full Text PDFDev Dyn
November 2024
Department of Life Sciences, Natural History Museum, London, UK.
Background: Tapeworms are parasitic flatworms that independently evolved a segmented body plan, historically confounding comparisons with other animals. Anteroposterior (AP) patterning in free-living flatworms and in tapeworm larvae is associated with canonical Wnt signaling and positional control genes (PCGs) are expressed by their musculature in regionalized domains along the AP axis. Here, we extend investigations of PCG expression to the adult of the mouse bile-duct tapeworm Hymenolepis microstoma, focusing on the growth zone of the neck region and the initial establishment of segmental patterning.
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