Let’s kick off the Fourth of July weekend with some biological fireworks! While we’ve added a few pyrotechnic sound effects just for fun, what you see in this video is the product of some serious research. Using a specialized microscope equipped with a time-lapse camera to image fluorescence-tagged proteins in real-time, an NIH-funded team has captured a critical step in the process of cell division, or mitosis: how filaments called microtubules (red) form new branches (green) and fan out to form mitotic spindles.
In this particular experimental system, the team led by Sabine Petry at Princeton University, Princeton, NJ, studies the dynamics of microtubules in a cell-free extract of cytoplasm taken from the egg of an African clawed frog (Xenopus laevis). Petry’s ultimate goal is to learn how to build mitotic spindles, molecule by molecule, in the lab. Such an achievement would mark a major step forward in understanding the complicated mechanics of cell division, which, when disrupted, can cause cancer and many other health problems.
Tags: biological fireworks, branching microtubule nucleation, branching microtubules, cell biology, cell division, chromosomes, fluorescence microscopy, frog, frog eggs, gamma-TuRC, microtubules, mitotic spindle, NIH Director’s 2016 New Innovator Award, Princeton’s 2017 Art of Science, Ran, TPX2, xenopus, Xenopus laevis
The video starts with a few individual microtubule filaments (red) growing linearly at one end (green). Notice the green “comets” that quickly appear, followed by a red trail. Those are new microtubules branching off. This continuous branching is interesting because microtubules were generally thought to grow linearly in animal cells (although branching had been observed a few years earlier in fission yeast and plant cells). The researchers, led by Sabine Petry, now at Princeton University, Princeton, NJ, showed for the first time that not only do new microtubules branch during cell division, but they do so very rapidly, going from a few branches to hundreds in a matter of minutes .