Please use this identifier to cite or link to this item: http://arks.princeton.edu/ark:/88435/dsp0112579s329
 Title: Examination of bacterial growth, cell shape maintenance, DNA segregation, and death in Caulobacter crescentus Authors: Yakhnina, Anastasiya Aleksandrovna Advisors: Gitai, Zemer Contributors: Molecular Biology Department Keywords: Caulobacter crescentuscell deathcell shapechromosome segregationcytoskeletonpeptidoglycan Subjects: Molecular biology Issue Date: 2013 Publisher: Princeton, NJ : Princeton University Abstract: Despite their long-standing role as comparatively simple model organisms, bacteria undergo very complex physiological processes. Their growth depends on the coordinated action of the peptidoglycan remodeling complexes, which include biosynthetic transpeptidases and transglycosylases as well as hydrolytic enzymes. While the roles of transpeptidases in specific modes of bacterial growth are well understood, this dissertation addresses the contribution of transglycosylases to the peptidoglycan synthesis in Caulobacter. We find that tranglycosylases are largely redundant, but the loss of CC0252 leads to a general defect in cell wall integrity. The remodeling complexes themselves are spatially controlled by the three-dimensional arrangements of cytoskeletal structures within the cells. In particular, elongation of most rod-shaped bacteria requires the actin homolog MreB, but despite the central importance of MreB to cell shape maintenance and viability, its regulation is poorly understood. We report the identification of MbiA, a small protein that genetically and biochemically interacts with MreB and whose overexpression mimics the MreB loss-of-function phenotype while also perturbing MreB localization. Bacterial chromosome segregation is also a complex, multistep process. We show that it progresses through several phases involving polar release of the origin, its slow initial motion, and the fast late motion dependent on the action of the polymer-forming ATPase ParA. Finally, we find that upon DNA damage, Caulobacter induces a BapE endonuclease and activates an apoptotic-like response, demonstrating the ability to undergo a process long thought to be the sole purview of eukaryotes. URI: http://arks.princeton.edu/ark:/88435/dsp0112579s329 Alternate format: The Mudd Manuscript Library retains one bound copy of each dissertation. Search for these copies in the library's main catalog Type of Material: Academic dissertations (Ph.D.) Language: en Appears in Collections: Molecular Biology

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