1. Master’s Thesis Abstract:
During cell division, each chromosome is replicated to produce two sister chromatids.
Replicated sister chromatids are held together by the cohesion machinery until they separate
during anaphase into two daughter cells. This process ensures that each daughter cell receives
the full complement of chromosomes. Ctf7p (Chromosome transmission fidelity) establishes
cohesion during S phase. Genetic interactions occur between CTF7 and POL30 ( encoding
PCNA), which suggest that PCNA might play a role in sister chromatid cohesion. In addition,
there is evidence for physical interactions between Ctf7p and RFC (Replication Factor C)
subunits which load PCNA onto DNA. RFC complexes also load a Rad17/Mec3/Ddc1
heterotrimeric ring onto DNA during repair. In light of these findings, we tested whether (1)
PCNA interacts physically with Ctf7p, (2) PCNA hads a role in cohesion and whether (3) Rad24p
and Elg1p, Rfc1p homologs involved in DNA repair and okazaki fragment maturation, play a role
in cohesion. We found that PCNA physically interacts with Ctf7p and that interaction is highly
specific, although a cohesion defect was not detected in pol30-104 allele. We also found that
Elg1p binds to Ctf7p as shown by GST pull down assay.