Recent studies have revealed that the DNA cross-inversion mechanism of topoisomerase II (topo II) not only removes DNA supercoils and DNA replication intertwines, but also produces small amounts of DNA knots within the clusters of nucleosomes that conform to eukaryotic chromatin. Here, we examine how transcriptional supercoiling of intracellular DNA affects the occurrence of these knots. We show that although (-) supercoiling does not change the basal DNA knotting probability, (+) supercoiling of DNA generated in front of the transcribing complexes increases DNA knot formation over 25-fold. The increase of topo II-mediated DNA knotting occurs both upon accumulation of (+) supercoiling in topoisomerase-deficient cells and during normal transcriptional supercoiling of DNA in TOP1 TOP2 cells. We also show that the high knotting probability (Pkn ≥ 0.5) of (+) supercoiled DNA reflects a 5-fold volume compaction of the nucleosomal fibers in vivo. Our findings indicate that topo II-mediated DNA knotting could be inherent to transcriptional supercoiling of DNA and other chromatin condensation processes and establish, therefore, a new crucial role of topoisomerase II in resetting the knotting-unknotting homeostasis of DNA during chromatin dynamics.

Transcriptional supercoiling boosts topoisomerase II-mediated knotting of intracellular DNA / Valdes, A.; Coronel, L.; Martinez-Garcia, B.; Segura, J.; Dyson, S.; Diaz-Ingelmo, O.; Micheletti, C.; Roca, J.. - In: NUCLEIC ACIDS RESEARCH. - ISSN 1362-4962. - 47:13(2019), pp. 6946-6955. [10.1093/nar/gkz491]

Transcriptional supercoiling boosts topoisomerase II-mediated knotting of intracellular DNA

Coronel, L.;Micheletti, C.;
2019

Abstract

Recent studies have revealed that the DNA cross-inversion mechanism of topoisomerase II (topo II) not only removes DNA supercoils and DNA replication intertwines, but also produces small amounts of DNA knots within the clusters of nucleosomes that conform to eukaryotic chromatin. Here, we examine how transcriptional supercoiling of intracellular DNA affects the occurrence of these knots. We show that although (-) supercoiling does not change the basal DNA knotting probability, (+) supercoiling of DNA generated in front of the transcribing complexes increases DNA knot formation over 25-fold. The increase of topo II-mediated DNA knotting occurs both upon accumulation of (+) supercoiling in topoisomerase-deficient cells and during normal transcriptional supercoiling of DNA in TOP1 TOP2 cells. We also show that the high knotting probability (Pkn ≥ 0.5) of (+) supercoiled DNA reflects a 5-fold volume compaction of the nucleosomal fibers in vivo. Our findings indicate that topo II-mediated DNA knotting could be inherent to transcriptional supercoiling of DNA and other chromatin condensation processes and establish, therefore, a new crucial role of topoisomerase II in resetting the knotting-unknotting homeostasis of DNA during chromatin dynamics.
47
13
6946
6955
Valdes, A.; Coronel, L.; Martinez-Garcia, B.; Segura, J.; Dyson, S.; Diaz-Ingelmo, O.; Micheletti, C.; Roca, J.
File in questo prodotto:
File Dimensione Formato  
NAR_2019_S(+)_knots_gkz491.pdf

accesso aperto

Tipologia: Versione Editoriale (PDF)
Licenza: Creative commons
Dimensione 4.16 MB
Formato Adobe PDF
4.16 MB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11767/111096
Citazioni
  • ???jsp.display-item.citation.pmc??? 7
  • Scopus 13
  • ???jsp.display-item.citation.isi??? 11
social impact