Abstract
The anaphase spindle plays an essential role in the chromosome separation. In general, its dynamics shows two phases. The first phase is the kinetochore microtubule shortening (anaphase A) and the second one is the spindle pole separation by sliding of the microtubule overlap zone and by pulling over the aster microtubules (anaphase B). However, in plant cells because they have an acentrosomal spindle, no conspicuous spindle elongation has been reported. In this study, we visualized microtubules and cell nuclei in transgenic tobacco BY-2 cells using GFP-tubulin and histone-RFP and quantified the spindle elongation and chromosome movement. Then we found a clear process of anaphase B in tobacco cells after the start of anaphase A. It suggests that the plant spindle has an elongatable structure. Now we investigate the spindle structure quantitatively in moss Physcomitrella patens to explore the variety of spindle dynamics between the plant species.
