Spatial Organization of Biological Fuctions | BPS Thematic Meeting

Spatial Organization of Biological Functions Meeting

Tuesday Speaker Abstracts

TOPOLOGY MEDIATED ORGANIZATION OF E. COLI CHROMOSOME IN SLOW AND FAST GROWTH CONDITIONS Apratim Chatterji 1 ; Debarshi Mitra 1 ; Shreerang Pande 1 ; Shailesh Sathe 1 ; 1 IISER Pune, Physics, Pune, India We elucidate the underlying mechanism of organization and segregation of the E. coli chromosomes in both slow and fast growth conditions, as it occurs concurrently with replication. We quantitatively match the organization of certain tagged loci (polymer segments) from our simulations [1], [2], [3], similar to those obtained from FISH experiments [4], [5], which is also consistent with HiC [6]. We also match the organization of the replication forks, reconciling the conflicting models of the train track and replication factory models of the motion of the replisome. We were able to reproduce the experiments by introducing a few long-range interactions, creating small loops within the chromosome. We also elucidate the underlying entropy based physical mechanism for the transport of one of the daughter OriCs from one pole to the other for the replicating C.crescentus chromosome, with suitable help from the ParABS system of proteins.[1] D. Mitra, S. Pande, and A. Chatterji, Soft Matter, 18, pp. 5615–5631 (2022). https://pubs.rsc.org/en/content/articlehtml/2022/sm/d2sm00734g[2] S. Pande, D. Mitra, and A. Chatterji, Physical Review E, 110, no. 5, (2024). https://journals.aps.org/pre/abstract/10.1103/PhysRevE.110.054401[3] D. Mitra, S. Pande, and A. Chatterji, Physical Review E, 106, (2022). https://journals.aps.org/pre/abstract/10.1103/PhysRevE.106.054502[4] J. A. Cass, N. J. Kuwada, B. Traxler, and P. A. Wiggins, Biophysical Journal, vol. 110, no. 12, pp. 2597–2609, 2016.[5] B. Youngren, H. J. Nielsen, S. Jun, and S. Austin, Genes and Development, vol. 28, no. 1, p. 71–84, Jan. 2014.[6] V. S. Lioy, A. Cournac, M. Marbouty, S. Duigou, J. Mozziconacci, O. Espéli, F. Boccard, and R. Koszul, Cell, vol. 172, no. 4, pp. 771– 783, 2018.

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