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  1. Article ; Online: Linker histone H1 regulates homeostasis of heterochromatin-associated cRNAs.

    Bujosa, Paula / Reina, Oscar / Caballé, Adrià / Casas-Lamesa, Anna / Torras-Llort, Mònica / Pérez-Roldán, Juan / Nacht, Ana Silvina / Vicent, Guillermo P / Bernués, Jordi / Azorín, Fernando

    Cell reports

    2024  Volume 43, Issue 5, Page(s) 114137

    Abstract: Chromatin-associated RNAs (cRNAs) are a poorly characterized fraction of cellular RNAs that co-purify with chromatin. Their full complexity and the mechanisms regulating their packaging and chromatin association remain poorly understood. Here, we address ...

    Abstract Chromatin-associated RNAs (cRNAs) are a poorly characterized fraction of cellular RNAs that co-purify with chromatin. Their full complexity and the mechanisms regulating their packaging and chromatin association remain poorly understood. Here, we address these questions in Drosophila. We find that cRNAs constitute a heterogeneous group of RNA species that is abundant in heterochromatic transcripts. We show that heterochromatic cRNAs interact with the heterogeneous nuclear ribonucleoproteins (hnRNP) hrp36/hrp48 and that depletion of linker histone dH1 impairs this interaction. dH1 depletion induces the accumulation of RNA::DNA hybrids (R-loops) in heterochromatin and, as a consequence, increases retention of heterochromatic cRNAs. These effects correlate with increased RNA polymerase II (RNAPII) occupancy at heterochromatin. Notably, impairing cRNA assembly by depletion of hrp36/hrp48 mimics heterochromatic R-loop accumulation induced by dH1 depletion. We also show that dH1 depletion alters nucleosome organization, increasing accessibility of heterochromatin. Altogether, these perturbations facilitate annealing of cRNAs to the DNA template, enhancing R-loop formation and cRNA retention at heterochromatin.
    Language English
    Publishing date 2024-04-24
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2649101-1
    ISSN 2211-1247 ; 2211-1247
    ISSN (online) 2211-1247
    ISSN 2211-1247
    DOI 10.1016/j.celrep.2024.114137
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: The zinc-finger protein Z4 cooperates with condensin II to regulate somatic chromosome pairing and 3D chromatin organization.

    Puerto, Marta / Shukla, Mamta / Bujosa, Paula / Pérez-Roldán, Juan / Torràs-Llort, Mònica / Tamirisa, Srividya / Carbonell, Albert / Solé, Carme / Puspo, Joynob Akter / Cummings, Christopher T / de Nadal, Eulàlia / Posas, Francesc / Azorín, Fernando / Rowley, M Jordan

    Nucleic acids research

    2024  

    Abstract: Chromosome pairing constitutes an important level of genome organization, yet the mechanisms that regulate pairing in somatic cells and the impact on 3D chromatin organization are still poorly understood. Here, we address these questions in Drosophila, ... ...

    Abstract Chromosome pairing constitutes an important level of genome organization, yet the mechanisms that regulate pairing in somatic cells and the impact on 3D chromatin organization are still poorly understood. Here, we address these questions in Drosophila, an organism with robust somatic pairing. In Drosophila, pairing preferentially occurs at loci consisting of numerous architectural protein binding sites (APBSs), suggesting a role of architectural proteins (APs) in pairing regulation. Amongst these, the anti-pairing function of the condensin II subunit CAP-H2 is well established. However, the factors that regulate CAP-H2 localization and action at APBSs remain largely unknown. Here, we identify two factors that control CAP-H2 occupancy at APBSs and, therefore, regulate pairing. We show that Z4, interacts with CAP-H2 and is required for its localization at APBSs. We also show that hyperosmotic cellular stress induces fast and reversible unpairing in a Z4/CAP-H2 dependent manner. Moreover, by combining the opposite effects of Z4 depletion and osmostress, we show that pairing correlates with the strength of intrachromosomal 3D interactions, such as active (A) compartment interactions, intragenic gene-loops, and polycomb (Pc)-mediated chromatin loops. Altogether, our results reveal new players in CAP-H2-mediated pairing regulation and the intimate interplay between inter-chromosomal and intra-chromosomal 3D interactions.
    Language English
    Publishing date 2024-03-23
    Publishing country England
    Document type Journal Article
    ZDB-ID 186809-3
    ISSN 1362-4962 ; 1362-4954 ; 0301-5610 ; 0305-1048
    ISSN (online) 1362-4962 ; 1362-4954
    ISSN 0301-5610 ; 0305-1048
    DOI 10.1093/nar/gkae198
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article: Somatic chromosome pairing has a determinant impact on 3D chromatin organization.

    Puerto, Marta / Shukla, Mamta / Bujosa, Paula / Perez-Roldan, Juan / Tamirisa, Srividya / Solé, Carme / de Nadal, Eulàlia / Posas, Francesc / Azorin, Fernando / Rowley, M Jordan

    bioRxiv : the preprint server for biology

    2023  

    Abstract: In the nucleus, chromatin is intricately structured into multiple layers of 3D organization important for genome activity. How distinct layers influence each other is not well understood. In particular, the contribution of chromosome pairing to 3D ... ...

    Abstract In the nucleus, chromatin is intricately structured into multiple layers of 3D organization important for genome activity. How distinct layers influence each other is not well understood. In particular, the contribution of chromosome pairing to 3D chromatin organization has been largely neglected. Here, we address this question in
    Language English
    Publishing date 2023-03-30
    Publishing country United States
    Document type Preprint
    DOI 10.1101/2023.03.29.534693
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: DNA Methylation Editing by CRISPR-guided Excision of 5-Methylcytosine.

    Devesa-Guerra, Iván / Morales-Ruiz, Teresa / Pérez-Roldán, Juan / Parrilla-Doblas, Jara Teresa / Dorado-León, Macarena / García-Ortiz, María Victoria / Ariza, Rafael R / Roldán-Arjona, Teresa

    Journal of molecular biology

    2020  Volume 432, Issue 7, Page(s) 2204–2216

    Abstract: Tools for actively targeted DNA demethylation are required to increase our knowledge about regulation and specific functions of this important epigenetic modification. DNA demethylation in mammals involves TET-mediated oxidation of 5-methylcytosine (5- ... ...

    Abstract Tools for actively targeted DNA demethylation are required to increase our knowledge about regulation and specific functions of this important epigenetic modification. DNA demethylation in mammals involves TET-mediated oxidation of 5-methylcytosine (5-meC), which may promote its replication-dependent dilution and/or active removal through base excision repair (BER). However, it is still unclear whether oxidized derivatives of 5-meC are simply DNA demethylation intermediates or rather epigenetic marks on their own. Unlike animals, plants have evolved enzymes that directly excise 5-meC without previous modification. In this work, we have fused the catalytic domain of Arabidopsis ROS1 5-meC DNA glycosylase to a CRISPR-associated null-nuclease (dCas9) and analyzed its capacity for targeted reactivation of methylation-silenced genes, in comparison to other dCas9-effectors. We found that dCas9-ROS1, but not dCas9-TET1, is able to reactivate methylation-silenced genes and induce partial demethylation in a replication-independent manner. We also found that reactivation induced by dCas9-ROS1, as well as that achieved by two different CRISPR-based chromatin effectors (dCas9-VP160 and dCas9-p300), generally decreases with methylation density. Our results suggest that plant 5-meC DNA glycosylases are a valuable addition to the CRISPR-based toolbox for epigenetic editing.
    MeSH term(s) 5-Methylcytosine/chemistry ; Arabidopsis/genetics ; Arabidopsis/metabolism ; Arabidopsis Proteins/antagonists & inhibitors ; Arabidopsis Proteins/genetics ; Arabidopsis Proteins/metabolism ; CRISPR-Associated Protein 9/genetics ; CRISPR-Associated Protein 9/metabolism ; CRISPR-Cas Systems ; Epigenesis, Genetic ; Gene Editing ; Nuclear Proteins/antagonists & inhibitors ; Nuclear Proteins/genetics ; Nuclear Proteins/metabolism ; Transcriptional Activation
    Chemical Substances Arabidopsis Proteins ; Nuclear Proteins ; ROS1 protein, Arabidopsis ; 5-Methylcytosine (6R795CQT4H) ; CRISPR-Associated Protein 9 (EC 3.1.-)
    Language English
    Publishing date 2020-02-19
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 80229-3
    ISSN 1089-8638 ; 0022-2836
    ISSN (online) 1089-8638
    ISSN 0022-2836
    DOI 10.1016/j.jmb.2020.02.007
    Database MEDical Literature Analysis and Retrieval System OnLINE

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