| Non-Scientific Abstract As budding yeast multiply,particular molecules
work to ensure that each division occurs without error. Identifying the mechanisms that underlie the
intricate control of these cells may aid in the understanding of cancer cells,which exhibit
uncontrollable cellular growth and proliferation. In this study,we investigate one particular control
point, mitotic exit, in an attempt to identify molecules that inhibit completion of the process.
Mitotic exit is achieved when a molecule, Cdc14, is released from the nucleus of the cell and degraded
in the cytoplasm.Molecules that inhibit completion of mitotic exit, in effect, are preventing Cdc14
degradation.We have identified a putative inhibitor of this process,Kin4, a protein kinase, a molecule
that phosphorylates a substrate. The future aim is to identify the moleculešs substrate and particular
role in mitotic exit.
Abstract In
the budding yeast, Saccharomyces cerevisiae, two pathways have been identified as regulators of
mitotic exit. In the mitotic exit network (MEN) pathway, LTE1 is a positive regulator of TEMIšs
activity. If it is deleted, the MEN pathway is deficient in promoting mitotic exit.The cdcfourteen
early anaphase release network (FEAR) pathway helps to recover some of this deficiency using a
mechanism not yet elucidated to activate ubiquitin-mediated degradation of mitotic cyclins via APC/C
activation.However, if SPO12 is deleted in addition LTE1, this double mutation is lethal to
cells.Using mTn3-LEU2 transposon mutagenesis to mutate a third gene,we expected to find a suppressor
mutation that effectively recovered this synthetic lethality. Our suppressor screen identified KIN4 as
an interesting candidate for suppression of the lte1 Δ, spo12 Δ |
