Chromosome condensation factor brn1p is required for chromatid separation in mitosis
Chromosome condensation factor brn1p is required for chromatid separation in mitosis
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DOI：
10.1091/mbc.11.4.1305
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发表时间：
2000-04-01
影响因子：
3.3
通讯作者：
Brinkley, BR
中科院分区：
文献类型：
--
作者：
Ouspenski, II;Cabello, OA;Brinkley, BR
本工作描述了无性果蝇和非洲爪哇凝集素亚基XCAP-H的发芽酵母同源物BRN1。果蝇蛋白是有丝分裂中染色体正确分离所必需的，非洲爪哇蛋白在有丝分裂染色体凝聚中起作用。突变的Brn1细胞在有丝分裂后期染色体凝集和姐妹染色单体分离分离方面存在缺陷。在突变体中，后期前的染色单体凝聚力得到了适当的保持。一些突变的Brn1细胞明显停滞在S期，提示Brn1p可能在细胞周期的这一阶段发挥作用。Brn1p是一种分布不均匀的核蛋白，其水平在有丝分裂时上调。BRN1的温度敏感突变可以通过过度表达一个新的基因YCG1来抑制，该基因与另一个非洲爪哇凝集素亚基XCAP-G同源。SMC2是染色体凝聚所必需的基因，也是XCAP-E凝聚素的同源物，它的过表达不能抑制brn1，这表明凝聚素复合体的成分具有功能专门化。
This work describes BRN1, the budding yeast homologue of Drosophila Barren and Xenopus condensin subunit XCAP-H. The Drosophila protein is required for proper chromosome segregation in mitosis, and Xenopus protein functions in mitotic chromosome condensation. Mutant brn1 cells show a defect in mitotic chromosome condensation and sister chromatid separation and segregation in anaphase. Chromatid cohesion before anaphase is properly maintained in the mutants. Some brn1 mutant cells apparently arrest in S-phase, pointing to a possible function for Brn1p at this stage of the cell cycle. Brn1p is a nuclear protein with a nonuniform distribution pattern, and its level is up-regulated at mitosis. Temperature-sensitive mutations of BRN1 can be suppressed by overexpression of a novel gene YCG1, which is homologous to another Xenopus condensin subunit, XCAP-G. Overexpression of SMC2, a gene necessary for chromosome condensation, and a homologue of the XCAP-E condensin, does not suppress brn1, pointing to functional specialization of components of the condensin complex.