A role for the Bacillus subtilis Structural Maintenance of Chromosomes (BsSMC) protein in chromosome organization and compaction
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Biology, 2002.
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| Format: | Thesis |
| Language: | eng |
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Massachusetts Institute of Technology
2005
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| Online Access: | http://hdl.handle.net/1721.1/8385 |
| _version_ | 1826188921899319296 |
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| author | Lindow, Janet C. (Janet Christine), 1974- |
| author2 | Alan D. Grossman. |
| author_facet | Alan D. Grossman. Lindow, Janet C. (Janet Christine), 1974- |
| author_sort | Lindow, Janet C. (Janet Christine), 1974- |
| collection | MIT |
| description | Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Biology, 2002. |
| first_indexed | 2024-09-23T08:06:44Z |
| format | Thesis |
| id | mit-1721.1/8385 |
| institution | Massachusetts Institute of Technology |
| language | eng |
| last_indexed | 2024-09-23T08:06:44Z |
| publishDate | 2005 |
| publisher | Massachusetts Institute of Technology |
| record_format | dspace |
| spelling | mit-1721.1/83852019-04-09T16:42:21Z A role for the Bacillus subtilis Structural Maintenance of Chromosomes (BsSMC) protein in chromosome organization and compaction Role for the BsSMC protein in chromosome organization and compaction Lindow, Janet C. (Janet Christine), 1974- Alan D. Grossman. Massachusetts Institute of Technology. Dept. of Biology. Massachusetts Institute of Technology. Dept. of Biology. Biology. Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Biology, 2002. Includes bibliographical references. All cells must compact their chromosomes in order for the DNA to fit inside the cell or nucleus. In Bacillus subtilis, and other bacteria, replication occurs simultaneously with the organization, compaction and segregation of newly duplicated chromosomal regions. My work indicates that the B. subtilis Structural Maintenance of Chromosomes (BsSMC) protein is involved in compacting and organizing the chromosome. Increasing the amount of supercoiling of DNA is a means to compact the chromosome. This thesis describes a role for BsSMC in supercoiling. I determined that BsSMC can alter the DNA topology of plasmids in vivo. There is also genetic evidence that BsSMC is involved in supercoiling. An smc null mutant is hypersensitive to inhibitors of DNA gyrase, which reduce the level of negative supercoiling in the cell. Conversely, depletion of Topoisomerase I, which increases the amount of negative supercoiling of the chromosome, partially suppresses the phenotype of an smc null mutant. These data are consistent with the model that BsSMC affects chromosome compaction by constraining positive supercoils. Interestingly, SMC-containing complexes in eukaryotes are able to constrain positive supercoils in vitro and affect chromosome architecture suggesting that there is a conserved function for SMC proteins in chromosome structure. I also determined the subcellular localization of BsSMC. I found that BsSMC is a moderately abundant protein that can bind to many regions of the chromosome. A portion of BsSMC localizes in a pattern similar to the replication machinery. (cont.) Simultaneous localization of BsSMC and a component of the replisome revealed that they are usually in the same region of the cell but are not always colocalized. Finally, the formation of BsSMC foci is dependent on the presence of the nucleoid but not ongoing replication. I propose that BsSMC is acting to compact newly replicated DNA by affecting DNA topology and is thereby facilitating the partitioning of sister chromosomes to opposite halves of the cell. by Janet C. Lindow. Ph.D. 2005-08-23T19:44:41Z 2005-08-23T19:44:41Z 2002 2002 Thesis http://hdl.handle.net/1721.1/8385 50575024 eng M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 130 leaves 9477059 bytes 9476813 bytes application/pdf application/pdf application/pdf Massachusetts Institute of Technology |
| spellingShingle | Biology. Lindow, Janet C. (Janet Christine), 1974- A role for the Bacillus subtilis Structural Maintenance of Chromosomes (BsSMC) protein in chromosome organization and compaction |
| title | A role for the Bacillus subtilis Structural Maintenance of Chromosomes (BsSMC) protein in chromosome organization and compaction |
| title_full | A role for the Bacillus subtilis Structural Maintenance of Chromosomes (BsSMC) protein in chromosome organization and compaction |
| title_fullStr | A role for the Bacillus subtilis Structural Maintenance of Chromosomes (BsSMC) protein in chromosome organization and compaction |
| title_full_unstemmed | A role for the Bacillus subtilis Structural Maintenance of Chromosomes (BsSMC) protein in chromosome organization and compaction |
| title_short | A role for the Bacillus subtilis Structural Maintenance of Chromosomes (BsSMC) protein in chromosome organization and compaction |
| title_sort | role for the bacillus subtilis structural maintenance of chromosomes bssmc protein in chromosome organization and compaction |
| topic | Biology. |
| url | http://hdl.handle.net/1721.1/8385 |
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