Regulation of Polyadenylation in Eukaryotic pre-mRNA.
processing of eukaryotic pre-mRNA is an essential step in the synthesis of mRNA in
living cells. It involves a coupled cleavage and polyadenylation reaction, in which the
pre-mRNA is cleaved at the cleavage site, followed by the processive addition of a
poly(A) tail to the upstream pre-mRNA transcript. The poly(A) tail is essential for the
stability and export of mature mRNAs ... read morefrom the nucleus, and contributes to translation
initiation in the cytoplasm. The Cleavage/Polyadenylation Factor (CPF) is one of the
factors responsible for 3' end processing in yeast cells, and is made up of proteins
that facilitate both cleavage and polyadenylation. My dissertation focuses on the
mechanisms that regulate 3' end processing in yeast cells, and how interactions between
the proteins that make up CPF play a role in this process. My thesis shows that
interactions at the N-terminus of Pap1, a subunit of CPF and the enzyme that catalyzes
poly(A) addition, inhibit and stimulate polyadenylation, and I propose a model in which
these interactions are controlled by phosphorylation. I also show that Fip1, another
subunit of CPF that recruits Pap1 to CPF, has a flexible linker in the middle of the
protein, and that removal or replacement of the linker affects the efficiency of
polyadenylation. The flexible linker might also facilitate the degradation of Fip1 and
suggests another mechanism for the regulation of the polyadenylation step in yeast
Thesis (Ph.D.)--Tufts University, 2011.
Submitted to the Dept. of Biochemistry.
Advisor: Claire Moore.
Committee: Andrew Bohm, Carol Kumamoto, and Gavin Schnitzler.
Keywords: Molecular biology, Biochemistry, and Microbiology.read less