Doctor of Philosophy (PhD)


Biological Sciences

Document Type



The yeast rDNA region is host to a number of transcriptional regulatory elements, which work in conjunction to generate essential RNA subunits of ribosomes, as well as protecting the region from DNA damage. The role of RNA polymerase III complex binding at the 5S gene on rDNA silencing in the NTS2 region was investigated, both by use of a TY1:MET15 reporter insert and a MET15 gene integration at an endogenous SphI site. It was discovered that Pol III complexes do have an effect on reporter expression in the NTS2 region, though the specific effect was different based on the method of reporter integration. The ability of Reb1p and Pol III complex binding sites to block RNA polymerase II read through transcription was also explored. Reb1p was also found to be able to block Pol II read through transcription, while a 5S gene was only able to partially block Pol II read through transcription, and did so in an orientation dependent manner. Finally, a novel strategy for reducing leaky transcription from inducible promoters was designed, which may be of benefit to the greater research community. These results suggest an interesting possibility that DNA-bound Pol III complexes at 5S genes has an impact on rDNA silencing, and may have a greater impact in the regulation in the rDNA region than originally thought.



Committee Chair

Donze, David