| Project/Area Number |
11640625
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
遺伝
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| Research Institution | Kyoto Institute of Technology (2000)
Aichi Cancer Center Research Institute (1999) |
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Principal Investigator |
H.INOUE Yoshihiro Kyoto Istitute of Technology, Drosophila Genetic Res.Ctr., Lecture, ショウジョウバエ遺伝資源センター, 講師 (90201938)
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| Co-Investigator(Kenkyū-buntansha) |
YAMAGUCHI Masamitsu Aichi Cancer Ctr.Res.Inst., Section Head, 増殖制御研究室, 室長 (00182460)
広瀬 富美子 愛知県がんセンター, 生物学部, 主任研究員 (60208882)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 2000: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Keywords | DNA replication / Drosophila / DNA polymerase / Pelement / MCM |
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| Research Abstract |
It has been reported that several variations of cell cycle are observed during Drosophila development. Most of larval cells undergoes endoreplication cycle which comprises repeated rounds of S phase. In contrast, the imaginal disc cells proliferate with conventional cell cycle consisted of Gl, S, G2 and M phases. We have identified a mutation for the 140 kD subunit of DNA replication factor, RF-C as a dominant suppressor of rough eye phenotypes induced by ectopic expression of DREF, a common transcription factor for many genes involved in DNA
replication. The mutant dies during larval/pupal stages because of DNA replication defects in imaginal disc cells that are mitotically proliferating, while any abnormalities in endoreplication was not evident in larval cells. Taking together that factors involved in DNA replication were supplied as maternal products, the phenotypes suggests an idea that the replication factor in endoreplication cycles consisting of consecutive rounds of S phases without intervening mitosis could be more stable than that in the mitotic DNA replication. Furthermore, we have isolated the genomic and cDNA clones for DNA polymerase e and determined the whole primary structure. Immunohistochemical analyses indicates that DNA polymerase e expresses in all proliferative tissues during Drosophila development. Also, we isolated two null mutants by imprecise excision of the P element, with a 1.8 kb long deletion in the regulatory region from outside of the gene to just before TATA box. Both null mutants dies at late embryonic stages, indicating the DNA polymerase e is indispensable for Drosophila DNA replication. The heterozygotes for the null mutations also show a significant delay in larval and pupal growth. These phenotypes suggest that a loss of DNA polymerase e affects on DNA replication in mitotic as well as endoreplication tissues.
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