Since RNA Polymerase II (RNAPII) transcribes much of the genome, it is well situated to encounter and initiate a response to various types of DNA damage. However, to date very little is known about any response of RNAPII to DNA damage outside of Transcription Coupled Nucleotide Excision Repair (TC-NER). A link between DNA damage response mechanisms and the C-terminal domain of RNAPII (CTD) is suggested by an overlap between proteins that bind the CTD and genes required for resistance to DNA damaging agents. In this thesis, I show that proper deployment of CTD associated proteins is required to respond to DNA damaging agents. Furthermore, I show that a CTD associated protein (Set2) is required for response to DNA damage, but its catalytic activity is not. Finally, I show that the recombinational ability of strains lacking the CTD kinase, Ctk1, is deficient. Based on these lines of evidence, I propose a novel CTD Associated DNA Damage Response (CAR) system of proteins that is required for proper response to DNA damaging agents.
