メタフェーズにおける姉妹染色体分離の二重阻害
O Stemmann1, H Zou, S A Gerber
1Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA.
Cell
|December 19, 2001
まとめ
姉妹染色体の分離には,活性分離酵素 (酵素) が必要です. 高濃度のCDC2活性が,リン酸化による分離を阻害し,この阻害性リン酸が除去されるまで,アナファゼを防止します.
科学分野:
- 細胞生物学 細胞生物学
- 分子生物学は分子生物学である.
- バイオケミストリー バイオケミストリー
背景:
- アナファーゼの発症は姉妹染色体分離に依存し,プロテアゼ分離酵素によって媒介されます.
- セパラーゼは,コヘシン複合体のサブユニットであるSCC1を割って,染色体の分離を可能にします.
- セパラーゼの活動は,セパラーゼを阻害するセキュリンと,リン酸化によって調節されます.
研究 の 目的:
- メタフェーズからアナフェーズへの移行中のセパレーズ活性調節を調査する.
- セキュリンが分解された場合でも分離を阻害するメカニズムを特定する.
- セパラーゼ機能の制御におけるリン酸化の役割を解明する.
主な方法:
- 細胞循環の調節を研究するために,Xenopusの卵エキスを用いた実験.
- バイオケミカルアッセイは,分離酵素活性と阻害を評価するためのものです.
- セパラーゼリン酸化部位のサイト指向型変異.
- 質量質量スペクトロメトリー 完ぺきな細胞で.
主要な成果:
- 高濃度のCDC2活性は,セキュリンから独立したメカニズムでセセパレージを無効化することによってアナフェーズを阻害する.
- セパラーゼの特定のリン酸化部位の変異は,高いCDC2活性下で染色体分離を救済する.
- このリン酸化部位は,メタフェーズでは完全にリン酸化され,無傷の細胞ではアナフェーズでは脱リン酸化されます.
結論:
- メタフェーズからアナフェーズへの移行におけるセパラーゼの活性化には,セキュリンの分解と阻害性リン酸の除去の両方が必要です.
- リン酸化は分離活性に対する重要な調節メカニズムとして作用し,姉妹染色体の間に合った分離を保証します.
関連する概念動画
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02:20Cohesins
Cohesin protein complexes are a molecular glue that holds two sister chromatids together. They play an important role both in mitosis and meiosis. In mitosis, all cohesin complexes present on the chromosomes are removed before the start of the anaphase stage.
Cohesin complexes in Meiotic Division
Meiosis involves two distinct rounds of chromosomal segregation and cell divisions— Meiosis I followed by Meiosis II – producing four daughter cells. Meiosis I includes the separation of homologous...
Cohesin complexes in Meiotic Division
Meiosis involves two distinct rounds of chromosomal segregation and cell divisions— Meiosis I followed by Meiosis II – producing four daughter cells. Meiosis I includes the separation of homologous...
02:57Attachment of Sister Chromatids
As cells progress into mitosis, the nuclear envelope breaks down, and the condensed chromosomes are exposed to the array of bipolar microtubules of the mitotic spindle. The kinetochore, a large, disc-shaped protein complex, is present at the centromere region of the sister chromatids and acts as a binding site for the microtubules. Usually, the plus-end of a single microtubule is embedded within the kinetochore. However, some kinetochores first establish lateral contact with the side-wall of a...
02:17Separation of Sister Chromatids
At the transition from prophase to metaphase, there is a reduction in cohesion along the chromosomal arms, resulting in the resolution of sister chromatids. However, residual cohesin connections remain to hold the sister chromatids together until the transition from metaphase to anaphase. The residual connection prevents any premature separation of sister chromatids, blocking the risks of aneuploidy within the daughter cells.
At the onset of anaphase, separase, a proteolytic enzyme, is...
At the onset of anaphase, separase, a proteolytic enzyme, is...