SIR2は,異なるrDNAの繰り返し間の再結合を調節するが,酵母における個々のrRNA遺伝子の内での再結合は調節しない
Takehiko Kobayashi1, Takashi Horiuchi, Prasad Tongaonkar
1National Institute for Basic Biology, Okazaki, Japan. koba@nibb.ac.jp
Cell
|May 13, 2004
まとめ
SIR2遺伝子は,rDNAにおける不平等な姉妹染色体の再結合を防止し,コヘシン構造を形成する. このメカニズムは,個々のrRNA遺伝子の内での再結合に有意な影響を与えない.
科学分野:
- 分子生物学は分子生物学である.
- 遺伝学 遺伝学とは
- クロマチン生物学 クロマチン生物学
背景:
- リボソームDNA (rDNA) の繰り返しの内での再結合は,SIR2やFOB1.1のような遺伝子によって調節される.
- SIR2に依存するクロマチンの構造は,rDNA再結合機構を抑制すると仮定されています.
研究 の 目的:
- rDNA再結合におけるSIR2の役割と,複製フォークのダイナミクスとDNA構造への影響について調査する.
- SIR2がrDNAの繰り返しの内での再結合に影響を与えるメカニズムを解明する.
主な方法:
- 複製のフォークアスト,DNAの二重鎖の断裂,ホリデイ・ジャンクションの形成を評価する.
- 個々のrRNA遺伝子の内のミトスの再結合率を測定する.
- コヘシンサブユニットMcd1p (Scc1p) とrDNAとの関連を定量化する.
主要な成果:
- sir2DeltaとSIR2株のFOB1依存の複製フォークアスト,DNA破裂,ホリデー結合の有意な差異はありません.
- 個々のrRNA遺伝子内のミト性再結合率に有意な差はありません.
- SIR2株と比較して,sir2Delta株におけるrDNAとのMcd1p (Scc1p) アソシエーションの有意な減少.
結論:
- SIR2は,おそらく特殊なコヘシン構造を通して,rDNAにおける不平等な姉妹染色体再結合を防ぐ.
- リコンビネーションを防止するSIR2の機能は,個々のrRNA遺伝子内のイベントに有意な影響を与えない.
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