The Machinery That Helps Divide Your Cells Self-Organizes Like an Active Liquid Crystal

Scientists at the Flatiron Institute and their collaborators have shown that spindles, the machinery that separates chromosomes during cell division, self-organize much like active liquid crystals. The finding comes from testing a theory using data from actual human cells, as detailed in a study published the week of February 9 in Proceedings of the National Academy of Sciences. Spindles consist of long, thin microtubules and motor proteins. Researchers combined light microscopy and electron microscopy data to examine microtubule interactions and organization. The active liquid crystal model accurately predicted overall spindle shape, microtubule orientation and density patterns in most cases. Suryanarayana Maddu, a first author and Flatiron Research Fellow, said the consistent results from different data sets indicate the patterns reflect real physical properties of the spindle. The theory did not fully capture the behavior of kinetochore microtubules, which attach to chromosomes and make up about 15 percent of the microtubule population. At length scales below 300 nanometers, the model also faced limits in predicting spindle behavior. The research, co-authored by Colm Kelleher and others, is part of an initiative called CCBx at the Flatiron Institute's Center for Computational Biology. It could eventually aid studies on fertility, in vitro fertilization and cancer treatments that target spindles, the scientists said.