Chromosome mechanics in vivo: quantitative analysis of nonrigid 3D chromosome motion in Drosophila embryos

摘要

Abstract: Chromosomes are often arranged into specific configurations. One example is the metaphase plate of the Drosophila embryo in which chromosomes are arranged into a parallel bundle. How is this configuration established and maintained? Quantitative analysis of chromosomes motion in vivo should help answer this question by providing a measure of the relevant mechanical properties of the chromosomes themselves. In addition, motion analysis will allow us to study interactions of chromosomes with the mitotic spindle. In order to analyze moving mitotic chromosomes, we acquire time-lapse 3D images of chromosomes in living Drosophila embryos, and then interactively model the chromosome configuration at each time point. A model-based motion estimation algorithm is then applied. From the motion estimate, we can visualize trajectories of different regions on the chromosomes, such as centromeres and telomeres, during metaphase and during prometaphase congression. In addition, quantitative estimates of mechanical properties such as mobility and flexibility can be computed. In this preliminary report we describe computational tools for tracking and visualizing 3D chromosome motion, and for detecting oscillations in position along the mitotic spindle.!11