Studies on the potential role of Ndt80 in the control of DNA replication during yeast meiosis
Date Issued
2015
Date
2015
Author(s)
Lin, Ying-Jyun
Abstract
Meiosis is characterized by a single round of DNA replication followed by two rounds of chromosome segregation. However, the mechanism to prevent DNA replication between the two rounds of division is not clear. In the budding yeast, the meiosis-specific transcription factor Ndt80 is pivotal to nuclear divisions and spore formation. Interestingly, ectopic expression of NDT80 in vegetative cells blocked budding and DNA replication. It is possible that Ndt80 also has the ability to inhibit DNA replication during meiosis. Therefore, we propose that Ndt80 might be involved in repressing another round of DNA replication between meiosis I and meiosis II. To test whether Ndt80 has the ability to inhibit replication in meiosis, we tried to precociously express NDT80 before the pre-meiotic DNA replication. We found cells that precociously expressed of NDT80 through the IME1 promoter at the initiation of meiosis could execute pre-meiotic DNA synthesis but were arrested at meiosis I. When NDT80 was expressed during the pre-meiotic incubation, in which most cells were at the post-RC stage, pre-meiotic DNA replication was partially repressed. However, the repression effect was not observed when NDT80 was expressed at the time that most cells were at G1 phase. These results suggest that Ndt80 might repress DNA replication by preventing pre-RC formation, but it could not repress DNA replication at the existing pre-RCs.
Subjects
yeast
meiosis
Ndt80
DNA replication
Type
thesis