Thesis advisor: Michelle Meyer / Prokaryotic ribosomes are key to cell viability and an important area of study in model bacterial organisms. Some ribosomal proteins negatively regulate their own synthesis and that of the polycistronic operons they occur within. If levels of an autoregulatory ribosomal protein are higher than necessary for normal ribosome assembly, it binds to the 5’-untranslated region of its own mRNA transcript, preventing further translation of itself and any other proteins on its operon. We and others have shown bacteria growth defects when overexpressing ribosomal proteins (e.g. L20 and S6:S18); therefore, we hypothesized that an overabundance of autoregulatory proteins would negatively affect cell fitness due to decreased expression of the operon gene products, many of which are essential components of the ribosome. The regulation of ribosomal proteins is best described in E. coli, so we decided to use it as a model organism to investigate how overexpression of specific ribosomal proteins would affect cell growth.
We examined the effects of overexpressing ribosomal proteins S15, S20, S2, S6:S18, S8, L20, L10, S1, L25, L7 and L1 on cell growth. We find the most severe growth defect in response to L20 overexpression. We performed rescue experiments for L20, L10, and S6:S18 by synthetically overexpressing the entire operon rather than just the regulatory protein. We find that this rescues the fitness of S6:S18 overexpression slightly, and L20 and L10 overexpression to a high degree. We also examined whether homologs of L20, L10, and S7 from B. subtilis and T. thermophilus induce the same changes in growth to deduce the regulatory interrelationships between different bacterial phyla. Bacillus L20 and L10 overexpression both showed drastic fitness defects. As our arsenal of effective antibiotics dwindles, our results suggest that targeting the ribosomal protein operons may be an effective area for pharmaceutical development. / Thesis (BS) — Boston College, 2017. / Submitted to: Boston College. College of Arts and Sciences. / Discipline: Arts and Sciences Honors Program. / Discipline: Biology.
| Identifer | oai:union.ndltd.org:BOSTON/oai:dlib.bc.edu:bc-ir_107395 |
| Date | January 2017 |
| Creators | Perryman, Matthew |
| Publisher | Boston College |
| Source Sets | Boston College |
| Language | English |
| Detected Language | English |
| Type | Text, thesis |
| Format | electronic, application/pdf |
| Rights | Copyright is held by the author, with all rights reserved, unless otherwise noted. |
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