在元相阶段对姐妹染色体分离的双重抑制
O Stemmann1, H Zou, S A Gerber
1Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA.
Cell
|December 19, 2001
概括
姐妹染色体分离需要活性分离酶 (一种酶). 高的CDC2活性通过酸化抑制分离,防止酶,直到这种抑制酸盐被移除.
科学领域:
- 细胞生物学 细胞生物学
- 分子生物学分子生物学
- 生物化学 生物化学
背景情况:
- 酶的开始取决于姐妹染色体的分离,由蛋白质酶分离酶介导.
- 分离酶切割SCC1,这是凝聚体复合物的子单元,允许染色体分离.
- 分离活性由抑制分离的securin和酸化来调节.
研究的目的:
- 为了研究在甲相-亚相过渡期间的分离活性调节.
- 为了确定抑制分离的机制,即使在securin被降解.
- 阐明酸化在控制分离功能中的作用.
主要方法:
- 使用Xenopus蛋提取物研究细胞循环调节的实验.
- 生物化学测试以评估分离酶活性和抑制.
- 分离酶酸化位点的位点定向突变发生.
- 在完整的细胞中进行定量质谱.
主要成果:
- 高的CDC2活性通过一种独立于securin的机制通过非激活分离酶来抑制酶.
- 在分离酶上特定酸化位点的突变在高CDC2活性下挽救了染色体分离.
- 在完整的细胞中,这种酸化部位在甲相中被完全酸化,并在亚相中被脱酸化.
结论:
- 在甲相-亚相过渡时的分离酶激活需要securin降解和抑制酸盐的去除.
- 酸化作为分离活性的关键调节机制,确保及时分离姐妹染色体.
相关概念视频
Cohesins
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...
Attachment 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...
Separation 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...
Cohesins
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...
Attachment 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...
Separation 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...


