Einzelzellbiologie

Abstrakt

The cycle of kinetochore-negative micronuclei and chromosome fragments in mitosis of HeLa cells

Xiuhong Zhou, Daxiang Li, Zhongwen Xie*, Erkang Jiang*, Lianping Wei, Fang Tao, Mei Yu, Shu Wang

Depending on whether kinetochores are present or not, MNi are further divided into kinetochore-negative MNi (Kâˆ'MNi) and kinetochore-positive MNi (K+MNi), which exhibit different mechanisms of micronucleus formation. However, the differences in the fate of Kâˆ'MNi and K+MNi are not yet fully understood. The present study aims to answer these questions. Methods: Here, HeLa CENP B-GFP H2B-mCherry cells were selected to distinguish K+MNi and Kâˆ'MNi in living cells. In the cells, MNi were identified by H2B-mCherry and further divided into K+MNi and Kâˆ'MNi, i.e., the K+MNi contained CENP B-GFP while the Kâˆ'MNi did not. Long-term live cell imaging was applied in the cells to record the dynamics of cell mitosis, especially of K+MNi and Kâˆ'MNi. Results: Our results show that the presence of Kâˆ'MN or K+MN did not lead to multipolar mitosis. Kâˆ'MN-bearing cells produced many more chromosome fragments than MN-free cells. Most of the chromosome fragments eventually fused with Kâˆ'MNi. K+MN-bearing cells produced more kinetochore-positive lagging chromosomes (K+LCs) and K+MNi than MN-free cells. Conclusion: The results suggested differences in the fate of K+MNi and Kâˆ'MNi during mitosis. The cycle of Kâˆ' MN â†' chromosome fragment â†' Kâˆ'MN may occur in generations of Kâˆ'MN-bearing cells, while a portion of K+MNi might be reintegrated into the main nucleus.