| dc.description | FACT (facilitates c&barbelow;hromatin t&barbelow;ransactions) is an essential conserved complex for chromatin modulation, and in yeast is comprised of the Cdc68 and Pob3 proteins. My thesis research has identified novel mutations of the Cdc68 subunit of FACT that result in defects in chromatin structure. These mutations cluster in the C-terminal region of Cdc68 which in addition to the identification of an N-terminal deletion mutation of cdc68 (missing approximately 40% of the coding sequence), has facilitated a concerted approach to understand the structure/function relationships for Cdc68, particularly in the context of the Cdc68-binding partner, Pob3. In particular, the regions responsible for Cdc68/Pob3 interaction(s) were determined. Additional genetic experiments to elucidate structure/function relationships for several mutant alleles of cdc68 were also carried out, including characterization of phenotypes associated with a range of mutant alleles, a dosage-suppressor selection approach, and screens for synthetic-lethal interactions of cdc68 N-terminal and C-terminal mutations. The conclusions from these studies include (1) identification of a role for the N-terminal domain of Cdc68 in FACT-mediated DNA replication and repair, (2) classification of Cdc68 C-terminal point mutations based on the ability to influence transcription-related processes or intracellular transport, (3) characterization of an overlapping essential function for the N-terminal and C-terminal domains of Cdc68, and (4) identification of Pkc1-signalling components as dosage suppressors of defective Cdc68 function that implicates FACT in regulation of cell integrity and morphogenesis. | en_US |
