Topoisomerase IIβ targets DNA crossovers formed between distant homologous sites to induce chromatin opening
| Autor: | Ryozo Kuwano, Jiyoung Kang, Masaru Tateno, Osamu Hosoya, Kuniaki Sano, Kimiko Tsutsui, Mary Miyaji, Norikazu Hara, Ken Tsutsui, Ryohei Furuta |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Gene isoform
Molecular biology Science Biochemistry Article chemistry.chemical_compound Transcriptional regulation Homologous chromosome Animals Protein Isoforms Rats Wistar Gene Neurons Multidisciplinary biology Topoisomerase Chromosome Cell Differentiation DNA Chromatin Cell biology Rats DNA-Binding Proteins DNA Topoisomerases Type II chemistry biology.protein Medicine Transcription Initiation Site |
| Zdroj: | Scientific Reports Scientific Reports, Vol 10, Iss 1, Pp 1-14 (2020) |
| ISSN: | 2045-2322 |
| Popis: | Type II DNA topoisomerases (topo II) flip the spatial positions of two DNA duplexes, called G- and T- segments, by a cleavage-passage-resealing mechanism. In living cells, these DNA segments can be derived from distant sites on the same chromosome. Due to lack of proper methodology, however, no direct evidence has been described so far. The beta isoform of topo II (topo IIβ) is essential for transcriptional regulation of genes expressed in the final stage of neuronal differentiation. Here we devise a genome-wide mapping technique (eTIP-seq) for topo IIβ target sites that can measure the genomic distance between G- and T-segments. It revealed that the enzyme operates in two distinctive modes, termed proximal strand passage (PSP) and distal strand passage (DSP). PSP sites are concentrated around transcription start sites, whereas DSP sites are heavily clustered in small number of hotspots. While PSP represent the conventional topo II targets that remove local torsional stresses, DSP sites have not been described previously. Most remarkably, DSP is driven by the pairing between homologous sequences or repeats located in a large distance. A model-building approach suggested that topo IIβ acts on crossovers to unknot the intertwined DSP sites, leading to chromatin decondensation. |
| Databáze: | OpenAIRE |
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