A quantitative analysis of the structure and dynamics of the bacterial chromosome

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Abstract/Contents

Abstract
Replication and segregation of the chromosome in the bacterium Caulobacter crescentus takes place simultaneously. Although it is known that each arm of the circular chromosome is on average linearly positioned along the cell length, the detailed configuration of the DNA in the cell is not well understood. Furthermore, in replicating bacterial cells, the centromere is segregated by a ParA-dependent mechanism and anchored at the pole, but the segregation mechanism for the rest of the chromosome is not known. To address these questions, I tracked the position and motion of multiple chromosomal loci both in non-replicating and replicating cells. By characterizing compaction of the DNA in non-replicating cells, I show that the DNA in the Caulobacter cells has the mean end-to-end distance that scale as (contour length)0.22, which suggests that compaction of the bacterial DNA is primarily driven by supercoiling. Analysis of the replication/segregation dynamics revealed that Caulobacter chromosome segregation is bimodal: Centromere-proximal DNA is segregated with the centromere at a slow pace whereas the rest of the DNA is segregated much faster. The dynamics of the centromere-distal DNA are consistent with a model where continuous compaction pulls the DNA toward the pole. The results provide a new perspective on the physical configuration of the non-replicating DNA and on the movement and compaction of newly replicated DNA immediately after replication and during its transport from the replisome to the cell poles.

Description

Type of resource text
Form electronic; electronic resource; remote
Extent 1 online resource.
Publication date 2011
Issuance monographic
Language English

Creators/Contributors

Associated with Hong, Sun-Hae
Associated with Stanford University, Department of Physics
Primary advisor Doniach, S
Primary advisor McAdams, Harley
Thesis advisor Doniach, S
Thesis advisor McAdams, Harley
Thesis advisor Shapiro, Lucy
Advisor Shapiro, Lucy

Subjects

Genre Theses

Bibliographic information

Statement of responsibility Sun-Hae Hong.
Note Submitted to the Department of Physics.
Thesis Thesis (Ph.D.)--Stanford University, 2011.
Location electronic resource

Access conditions

Copyright
© 2011 by Sun-Hae Hong
License
This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).

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