Limits of Chromosome Compaction by Loop-Extruding Motors
During mitosis, human chromosomes are linearly compacted about 1000-fold by loop-extruding motors. Recent experiments have shown that condensins extrude DNA loops but in a “one-sided” manner. This contrasts with existing models, which predict that symmetric, “two-sided” loop extrusion accounts for m...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
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American Physical Society
2019-07-01
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| Series: | Physical Review X |
| Online Access: | http://doi.org/10.1103/PhysRevX.9.031007 |
| _version_ | 1818727532168478720 |
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| author | Edward J. Banigan Leonid A. Mirny |
| author_facet | Edward J. Banigan Leonid A. Mirny |
| author_sort | Edward J. Banigan |
| collection | DOAJ |
| description | During mitosis, human chromosomes are linearly compacted about 1000-fold by loop-extruding motors. Recent experiments have shown that condensins extrude DNA loops but in a “one-sided” manner. This contrasts with existing models, which predict that symmetric, “two-sided” loop extrusion accounts for mitotic chromosome compaction. We explore whether one-sided extrusion, as it is currently seen in experiments, can compact chromosomes by developing a mean-field theoretical model for polymer compaction by motors that actively extrude loops and dynamically turnover. The model establishes a stringent upper bound of only about tenfold for compaction by strictly one-sided extrusion. We confirm this result with stochastic simulations. Thus, strictly one-sided extrusion as it has been observed so far cannot be the sole mechanism of chromosome compaction. However, as shown by the model, other two-sided or effectively two-sided mechanisms can achieve sufficient compaction. |
| first_indexed | 2024-12-17T22:15:35Z |
| format | Article |
| id | doaj.art-36488806a02e493bacfc702fb0678587 |
| institution | Directory Open Access Journal |
| issn | 2160-3308 |
| language | English |
| last_indexed | 2024-12-17T22:15:35Z |
| publishDate | 2019-07-01 |
| publisher | American Physical Society |
| record_format | Article |
| series | Physical Review X |
| spelling | doaj.art-36488806a02e493bacfc702fb06785872022-12-21T21:30:37ZengAmerican Physical SocietyPhysical Review X2160-33082019-07-019303100710.1103/PhysRevX.9.031007Limits of Chromosome Compaction by Loop-Extruding MotorsEdward J. BaniganLeonid A. MirnyDuring mitosis, human chromosomes are linearly compacted about 1000-fold by loop-extruding motors. Recent experiments have shown that condensins extrude DNA loops but in a “one-sided” manner. This contrasts with existing models, which predict that symmetric, “two-sided” loop extrusion accounts for mitotic chromosome compaction. We explore whether one-sided extrusion, as it is currently seen in experiments, can compact chromosomes by developing a mean-field theoretical model for polymer compaction by motors that actively extrude loops and dynamically turnover. The model establishes a stringent upper bound of only about tenfold for compaction by strictly one-sided extrusion. We confirm this result with stochastic simulations. Thus, strictly one-sided extrusion as it has been observed so far cannot be the sole mechanism of chromosome compaction. However, as shown by the model, other two-sided or effectively two-sided mechanisms can achieve sufficient compaction.http://doi.org/10.1103/PhysRevX.9.031007 |
| spellingShingle | Edward J. Banigan Leonid A. Mirny Limits of Chromosome Compaction by Loop-Extruding Motors Physical Review X |
| title | Limits of Chromosome Compaction by Loop-Extruding Motors |
| title_full | Limits of Chromosome Compaction by Loop-Extruding Motors |
| title_fullStr | Limits of Chromosome Compaction by Loop-Extruding Motors |
| title_full_unstemmed | Limits of Chromosome Compaction by Loop-Extruding Motors |
| title_short | Limits of Chromosome Compaction by Loop-Extruding Motors |
| title_sort | limits of chromosome compaction by loop extruding motors |
| url | http://doi.org/10.1103/PhysRevX.9.031007 |
| work_keys_str_mv | AT edwardjbanigan limitsofchromosomecompactionbyloopextrudingmotors AT leonidamirny limitsofchromosomecompactionbyloopextrudingmotors |