Multiple modes of DNA compaction by protamine.
| Autor: | Ahlawat V; Department of Chemistry and Department of Physics, University of Illinois Chicago, Chicago, United States., Zhou HX; Department of Chemistry and Department of Physics, University of Illinois Chicago, Chicago, United States. |
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| Jazyk: | angličtina |
| Zdroj: | BioRxiv : the preprint server for biology [bioRxiv] 2023 Dec 08. Date of Electronic Publication: 2023 Dec 08. |
| DOI: | 10.1101/2023.12.08.570784 |
| Abstrakt: | In sperm cells, protamine replaces histones to compact DNA 10-20 times more than in somatic cells. To characterize the extreme compaction, we employed confocal microscopy and optical tweezers to determine the conformations and stability of protamine-bound λ-DNA. Confocal images show increasing compaction of λ-DNA at increasing protamine concentration. In the presence of protamine, single λ-DNA molecules form bends and loops that unravel at 10-40 pN forces as well as coils that shorten the contour length by up to 40% and withstand forces strong enough (~55 pN) for strand separation. Strand separation nucleates coils, indicating protamine insertion into DNA bases. Protamine may participate in both local and higher-order chromatin organization, leading to extreme compaction and global transcription silencing. Competing Interests: Competing interests: Authors declare that they have no competing interests. |
| Databáze: | MEDLINE |
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