| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2000: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1999: ¥2,200,000 (Direct Cost: ¥2,200,000)
|
|---|
| Research Abstract |
In eukaryotes, the ATM and ATR family proteins play a critical role in the DNA damage and replication checkpoint controls. These proteins are characterized by a kinase domain related to the phosphatidylinositol (PI) 3-kinase, but have the ability to phosphorylate proteins. In budding yeast, the ATR family protein Mec1/Esr1 is essential for checkpoint responses and cell growth. We have isolated the PIE1 gene in atwo-hybrid screen for proteins that interact with Mec1 and show that Pie1 interacts physically with Mec1 in vivo. Like MEC1, PIE1 is essential for cell growth, and deletion of the PIE1 gene causes defects in the DNA damage and replication block checkpoints similar to those observed in mec1 mutants. Rad53 hyperphosphorylation following DNA damage and replication block is also decreased in pie1 cells as found in mec1 cells. Pie1 exhibits a limited homology to fission yeast Rad26 which forms a complex with the ATR family protein Rad3. Mutaion of the region in Pie1 homologous to Rad26 results in a phenotype similar to that of the pie1 mutation. Mec1 protein kinase activity appears to be essential for checkpoint responses and cell growth. However, Mec1 kinase activity is unaffected by the pie1 mutation, suggesting that Pie1 regulates some essential funtion other than Mec1 kinase activity. Thus, Pie1 is structurally and functionally related to Rad26, and interacts with Mec1 to control checkpoints and cell proliferation.
|
