Date of Award
1-1-2025
Degree Type
Dissertation
Degree Name
Doctor of Philosophy in Biological and Environmental Sciences
Specialization
Cell & Molecular Biology
Department
Cell & Molecular Biology
First Advisor
Jodi Camberg
Abstract
Cell division is one of the most well conserved biological processes undergone by prokaryotes. The hallmark of division is the establishment of the large cytoskeletal protein ring complex known as the Z-ring. The regulation of this ring, positioning of the ring at the future site of septation, and subsequent septation into identical progeny cells are the focus of many areas of study. Two systems will be the focus of this thesis. The first is the Min system which regulates the placement of the FtsZ-ring by moving across the longitudinal axis of the cell. The second is the peptidoglycan (PG) synthesis complex that allows for formation of new cell wall material. We will focus on the protein FtsN. The PG-synthesis complex is comprised of the proteins necessary for the assembly of new cell wall material during division. This includes the proteins involved in the longitudinal cell wall synthesis, such as PBP1a and PBP1b, as well as the proteins involved with inserting new PG at the division site, FtsN, FtsQ-FtsB-FtsL, and FtsW-FtsI. We will utilize genetic and biochemical tools such as fluorescent fusion proteins and purified proteins to deter-mine how the Min system functions to regulate FtsZ-ring assembly, and how the protein FtsN interacts with early division proteins to facilitate septation. We found that of the three Min proteins, MinC, MinD, and MinE, MinC plays a surprising role in regulating MinD oscillation. We also found that Min oscillation is differentially active during different growth states and modulated by the protease machine ClpXP, through direct alteration of the cellular levels of MinD. Finally, we found that FtsN forms a translateral division complex with the early division proteins FtsZ, FtsA, and peptidoglycan, and may play a role in modulating the lipid reorganzing properties of FtsA to facilitate the shape change that occurs during septation.
Creative Commons License
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Recommended Citation
Ferreira, Colby Mils, "GENETIC AND BIOCHEMICAL MECHANISMS CONTROLLING DIVISOME LOCALIZATION AND SEPTATION DURING THE ESCHERICHIA COLI CELL CYCLE" (2025). Open Access Dissertations. Paper 4452.
https://digitalcommons.uri.edu/oa_diss/4452