After the invention of time-lapse photography, the mechanics of the mitotic spindle started caming into focus, including its dynamic relationship to chromosomal separation. By the mid 1960's Shinya Inoue, a pioneer in live cell imaging, used his ground-breaking polarization microscopes to demonstrate that the spindle's fibrils could reversibly polymerize. This data lead to his landmark hypothesis that the polymerization and depolymerization reactions generated the forces pulling chromosomes apart during prometaphase and anaphase.

This time-lapse sequence of a purple urchin embryo (Strongylocentrotus purpuratus) depicts a single mitotic cycle in which all of the cells in the 28-cell embryo undergo mitosis nearly synchronously. Each image is a projection of a focal series of 15 1-micron confocal sections with frames 40-seconds apart. Microtubules and chromosomes are labeled with 3xGFP-Ensconsin (cyan) and = mCherry-Histone H2B (gold), respectively.

Video courtesy of By George von Dassow, University of Oregon.

See more cell cycle images in the Cell Picture Show: [ Ссылка ]

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