The survival of all organisms depends on the faithful transmission of DNA from one cell to its daughter cell. Cells respond to DNA damage by arresting the cell cycle and inducing the transcription of DNA repair genes. The Crt 1 protein has been identified as a key regulator of DNA damage-induced transcription of the genes encoding ribonucleotide reductase (RNR). The broad, long-term objective of this research program is to use modem methods in molecular genetics and biochemistry to understand the mechanisms underlying cellular response to DNA damage. The focus of this project is on the functional studies of Crtl, and to relate this understanding to the regulation of DNA damage response. This proposal also seeks to investigate CRT1-independent mechanism(s) involved in DNA damage-induced transcription.
Specific aims of the proposed research are: (1) To characterize the regulation of Crt 1 activities by the upstream checkpoint kinases in order to understand the negative feedback mechanism of the CRTl-mediated DNA damage response. (2) To characterize the interactions between Crtl and the general repressor complex Ssn6/Tup 1 in response to DNA damage in order to understand how the DNA damage checkpoint controls the switch from the repressed state to the induced state. (3) To determine CRTl-independent mechanism(s) involved in the DNA damage-induced transcription of the RNR genes with the ultimate aim of understanding the interplay among different regulatory pathways controlled by the DNA damage checkpoint. Failure of DNA damage response results in genomic instability and cancer predisposition. As a result, this research will contribute to an increased understanding of the complex biology of DNA damage and repair. These studies will also be critical in guiding our efforts to target the DNA damage response process for cancer diagnosis, prevention, and treatment.
