TRUSTEES OF TUFTS COLLEGE INC
"Synthesis of mRNA in eukaryotes, and its utilization in the cytoplasm, requires modification of the RNA’s 3’ end by addition of a poly(A) tail. This process also serves as an important point at which the cell can regulate the type and amount of mRNA derived from a particular gene. mRNA 3’ end formation occurs in a surprisingly large complex that is well conserved from yeast to mammals. In the yeast S. cerevisiae, it is composed of two multi-subunit factors called CPF and CF I, whose subunits have been identified. However, little is known about how these 20 proteins cooperate with each other to insure processing that is accurate as well as coupled in a timely fashion to other events in mRNA synthesis and packaging. With the 3’-end processing components now in hand, we have a unique opportunity to rigorously address the mechanism by which this essential and universal step in gene expression occurs and is regulated.
Our central hypothesis is that definable rearrangements of protein partners occur within the complex as it evaluates the authenticity of the processing site, commits to cleavage at the poly(A) site, reorganizes to position the poly(A) polymerase for tail synthesis, and releases the final RNA product. Our objective is to understand how such reorganizations drive the cycle of mRNA 3’ end processing. We have identified four events that are likely to be critical transition points in this cycle yet whose underlying mechanisms are not understood. Using yeast as our model system, we are investigating these transition points by pursuing the specific aims unchanged from the original grant.