Universal Loop Statistics from Active Extrusion with Kinetic Barriers
Fuente:
arXiv
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| Autori principali: | , , |
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| Natura: | Preprint |
| Pubblicazione: |
2026
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| _version_ | 1866913040676421632 |
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| author | Chervinskaya, A. Metzler, R. Polovnikov, K. E. |
| author_facet | Chervinskaya, A. Metzler, R. Polovnikov, K. E. |
| contents | We develop a kinetic theory of cohesin-driven loop extrusion on a disordered chromatin track with transient barriers. In the stationary state, the mean loop size is shown to obey a universal law determined by the bare processivity and a renormalized obstacle density. Beyond the mean, one-sided extrusion always yields a single-exponential loop-length distribution, whereas two-sided extrusion produces a finite sum of exponential modes and, generically, a peaked distribution. Experimental CTCF-anchored loop statistics exhibit such a peak, thereby providing a direct discriminator of extrusion symmetry. The theory therefore establishes a unified framework for disorder-limited loop extrusion and supports a scenario in which both cohesin arms actively operate in living cells. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2604_15527 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Universal Loop Statistics from Active Extrusion with Kinetic Barriers Chervinskaya, A. Metzler, R. Polovnikov, K. E. Soft Condensed Matter Biological Physics Biomolecules We develop a kinetic theory of cohesin-driven loop extrusion on a disordered chromatin track with transient barriers. In the stationary state, the mean loop size is shown to obey a universal law determined by the bare processivity and a renormalized obstacle density. Beyond the mean, one-sided extrusion always yields a single-exponential loop-length distribution, whereas two-sided extrusion produces a finite sum of exponential modes and, generically, a peaked distribution. Experimental CTCF-anchored loop statistics exhibit such a peak, thereby providing a direct discriminator of extrusion symmetry. The theory therefore establishes a unified framework for disorder-limited loop extrusion and supports a scenario in which both cohesin arms actively operate in living cells. |
| title | Universal Loop Statistics from Active Extrusion with Kinetic Barriers |
| topic | Soft Condensed Matter Biological Physics Biomolecules |
| url | https://arxiv.org/abs/2604.15527 |