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In budding yeast there exist regulators that control the steps in the process of forming the new daughter cell. Some of these regulators are called the mitotic exit network (MEN), which help the cell go from mitosis to G1.

We have been studying cell cycle control in the budding yeast K.lactis. Our K.lactis temperature sensitive mutant, RCY339, arrests after anaphase, which is suggested by its large bud, segregated DNA, and elongated spindle at the non-permissive temperature. A candidate gene altered in our mutant is CDC14, the last gene in the MEN pathway. A wild type copy of the K.lactis CDC14 gene complements the temperature sensitive defect in RCY339. However, it remained to be determined whether suppression was occurring, or if CDC14 was indeed mutated. In this study, classical genetic tests were used to confirm whether or not CDC14 contains the mutation that has caused RCY339 to arrest after anaphase. Results from these tests verified that the ts mutation in RCY339 is linked to the CDC 14 locus. The cdc14 allele of RCY339 was sequenced, to show that a mutation indeed existed, causing an amino acid change from a conserved proline to a serine in the encoded protein. Due to similarities observed in the cdc 14 mutant in K.lactis and S.cerevisiae, a S. cerevisiae cdc14 mutant was transformed with a wild type copy of CDC14 from K.lactis. Our transformation was no longer temperature sensitive, leading us to believe that CDC14 proteins from S.cerevisiae and K.lactis are functionally equivalent.