The control mechanisms of Ndt80 activity by the pachytene checkpoint
Date Issued
2005
Date
2005
Author(s)
Chang, Chun-Yu
DOI
en-US
Abstract
Mutants that confer defects in meiotic recombination (e.g., zip1) will trigger the checkpoint mechanism to arrest cells at the pachytene stage of meiosis. One of the control targets of the pachytene checkpoint is Ndt80. Ndt80 is a meiosis-specific protein that activates transcription of the middle sporulation genes, including genes required for nuclear divisions and spore formation. The Ndt80 activity is regulated by the pachytene checkpoint. Therefore, NDT80 is a critical factor which controls the progression from the pachytene into meiosis I.
Previous studies have isolated NDT80-bc, a dominant NDT80 mutant, which is not regulated by the pachytene checkpoint. Interestingly, the zip1 NDT80/NDT80-bc cells displayed a delay in nuclear division and spore formation, suggesting that inactive Ndt80 might exist and interfere with the activity of Ndt80-bc. In order to explore the regulatory mechanism of the pachytene checkpoint on Ndt80, we tried to use different epitopes to label Ndt80 and Ndt80-bc, respectively. Among all of these tagged Ndt80 and Ndt80-bc, NDT80-6XHA/NDT80-bc-6XMYC heterozygous in wild-type and zip1 were used to monitor the difference between Ndt80 and Ndt80-bc simultaneously. The zip1 NDT80-6XHA/NDT80-bc-6XMYC cells also displayed a delay in the kinetics of nuclear division and spore formation. We found that there is no significant difference in kinetics of protein expression between Ndt80 and Ndt80-bc in the zip1 NDT80-6XHA/NDT80-bc-6XMYC cells. Cytological analyses showed that the kinetics of nuclear import between Ndt80 and Ndt80-bc were different in zip1 NDT80-6XHA/NDT80-bc-6XMYC. Our results suggest that the Ndt80 activity is probably controlled by the pachytene checkpoint at the step of nuclear import.
Subjects
酵母菌
減數分裂
Ndt80
粗絲期檢控點
budding yeast
meiosis
pachytene checkpoint
Type
other
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