The aurora B kinase AIR-2 regulates kinetochores during mitosis and is required for separation of homologous chromosomes during meiosis
The aurora B kinase AIR-2 regulates kinetochores during mitosis and is required for separation of homologous chromosomes during meiosis
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DOI：
10.1016/s0960-9822(02)00820-5
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发表时间：
2002-05-14
期刊：
影响因子：
9.2
通讯作者：
Glotzer, M
中科院分区：
文献类型：
--
作者：
Kaitna, S;Pasierbek, P;Glotzer, M
背景资料：有丝分裂染色体的分离依赖于双定向和从纺锤体两极发出的微管对姐妹着丝粒的捕获以及姐妹染色单体凝聚力的近同步丧失。相反，在减数分裂I期间，姐妹动粒朝向相同的极，并且同源动粒被从相反的纺锤体极发出的微管捕获。此外，存在防止减数分裂I期间内聚完全丧失的机制。这些特征确保同源物在减数分裂I期间分离，而姐妹染色单体保持在一起直到减数分裂II。在有丝分裂过程中，着丝粒的定向和减数分裂过程中内聚的不同步丧失的机制目前还不清楚。极光B激酶AIR-2不是姐妹染色单体分离所必需的，但它是染色体分离所必需的。中期凝聚素的募集需要AIR-2;然而，凝聚素在前中期发挥作用，不依赖于AIR-2。在分裂中期，AIR-2可能通过抑制染色单体与纺锤体两极的结合，促进染色体向分裂中期板的聚集。在AIR-2缺失的卵母细胞减数分裂过程中，二价体的聚集似乎正常，但分离失败。AIR-2在减数分裂二价体上的定位表明这种激酶通过促进单个交叉远端的凝聚力的丧失来促进同源物的分离。灭活的磷酸酶，拮抗AIR-2导致过早分离的染色单体在减数分裂1，在分离依赖reaction.Conclusions：极光B功能，以解决交叉在减数分裂I和有丝分裂过程中调节动粒功能。凝聚素介导的染色体凝聚在前期，和凝聚素独立的途径有助于染色体凝聚在中期。
Background: Mitotic chromosome segregation depends on bi-orientation and capture of sister kinetochores by microtubules emanating from opposite spindle poles and the near synchronous loss of sister chromatid cohesion. During meiosis I, in contrast, sister kinetochores orient to the same pole, and homologous kinetochores are captured by microtubules emanating from opposite spindle poles. Additionally, mechanisms exist that prevent complete loss of cohesion during meiosis I. These features ensure that homologs separate during meiosis I and sister chromatids remain together until meiosis II. The mechanisms responsible for orienting kinetochores in mitosis and for causing asynchronous loss of cohesion during meiosis are not well understood.Results: During mitosis in C. elegans, aurora B kinase, AIR-2, is not required for sister chromatid separation, but it is required for chromosome segregation. Condensin recruitment during metaphase requires AIR-2; however, condensin functions during prometaphase, independent of AIR-2. During metaphase, AIR-2 promotes chromosome congression to the metaphase plate, perhaps by inhibiting attachment of chromatids to both spindle poles. During meiosis in AIR-2-depleted oocytes, congression of bivalents appears normal, but segregation fails. Localization of AIR-2 on meiotic bivalents suggests this kinase promotes separation of homologs by promoting the loss of cohesion distal to the single chiasma. Inactivation of the phosphatase that antagonizes AIR-2 causes premature separation of chromatids during meiosis 1, in a separase-dependent reaction.Conclusions: Aurora B functions to resolve chiasmata during meiosis I and to regulate kinetochore function during mitosis. Condensin mediates chromosome condensation during prophase, and condensin-independent pathways contribute to chromosome condensation during metaphase.