Department of Insect Biomedical Research, Centre for Advanced Insect Research Promotion, Kyoto Institute of Technology, Kyoto 606-8585, Japan.
Department of Insect Biomedical Research, Centre for Advanced Insect Research Promotion, Kyoto Institute of Technology, Kyoto 606-8585, Japan
J Cell Sci. 2021 Mar 26;134(6):jcs251231. doi: 10.1242/jcs.251231.
After centrosome duplication, centrioles elongate before M phase. To identify genes required for this process and to understand the regulatory mechanism, we investigated the centrioles in premeiotic spermatocytes expressing fluorescently tagged centriolar proteins. We demonstrated that an essential microtubule polymerisation factor, Orbit (the CLASP orthologue, encoded by ), accumulated at the distal end of centrioles and was required for the elongation. Conversely, a microtubule-severing factor, Klp10A, shortened the centrioles. Genetic analyses revealed that these two proteins functioned antagonistically to determine centriole length. Furthermore, Cp110 in the distal tip complex was closely associated with the factors involved in centriolar dynamics at the distal end. We observed loss of centriole integrity, including fragmentation of centrioles and earlier separation of the centriole pairs, in -null mutant cells either overexpressing Orbit or depleted of Excess centriole elongation in the absence of the distal tip complex resulted in the loss of centriole integrity, leading to the formation of multipolar spindle microtubules emanating from centriole fragments, even when they were unpaired. Our findings contribute to understanding the mechanism of centriole integrity, disruption of which leads to chromosome instability in cancer cells.
中心体复制后，在 M 期前拉长。为了鉴定这个过程所需的基因，并了解调控机制，我们在表达荧光标记的中心体蛋白的减数分裂前期精母细胞中研究了中心体。我们证明，一种必需的微管聚合因子，Orbit（由 编码的 CLASP 同源物），在中心体的远端积累，并且是伸长所必需的。相反，微管切割因子 Klp10A 缩短了中心体。遗传分析表明，这两种蛋白以拮抗的方式发挥作用，决定中心体的长度。此外，远端尖端复合物中的 Cp110 与参与远端中心体动力学的因子密切相关。我们观察到在 -null 突变体细胞中，中心体完整性的丧失，包括中心体的碎片化和中心体对更早的分离，在过表达 Orbit 或 耗尽的情况下都有发生。在没有远端尖端复合物的情况下，过量的中心体伸长导致中心体完整性的丧失，导致从中心体片段发出的多极纺锤体微管的形成，即使它们没有配对。我们的发现有助于理解中心体完整性的机制，这种完整性的破坏导致癌细胞中的染色体不稳定。
