Metaphase Kinetochore Dynamics: In this HeLa cell, which is expressing both a kinetochore marker (EGFP-CENP-B) and a centrosome marker (Venus-centrin), one can visualize the dynamic nature of kinetochore movements during metaphase. At this stage in mitosis, sister kinetochore pairs, seen as paired dots oriented parallel to the x-axis, are attached to opposite spindle poles, marked by the two pairs of venus centrin dots near the left and right edges of the movie (usually oriented perpendicular to the x-axis in this movie). Kinetochores in metaphase HeLa cells typically undergo oscillatory movements around the equator of the spindle with average oscillation amplitudes of 1.2 microns. The sister kinetochores display primarily coordinated movements but also move relative to each other, which can be seen as increases and decreases in the distance between the sisters. These movements are highly coordinated with the dynamics of microtubules attached to the kinetochores. Note that the centrin dots are approximately 12 microns apart at the start of the movie. This movie was part of a set that won first place in the 2007 ASCB Celldance contest.