Divide and conquer: investigating the mechanisms behind mitosis

Soon after a sperm meets an egg, the single fertilized cell splits into two cells, then four, and then eight. Cell division is responsible for producing each of the trillions of cells present in every human body. During adulthood, division supplies replacements for cells lost to age, injury, and disease, but it can also form the basis for illnesses such as cancer. Despite the importance of mitosis in development and medicine, researchers have much to learn about the molecular mechanisms that regulate it. Cell biologist Rebecca Heald of the University of California, Berkeley, is striving to iron out these details. Heald's work concentrates on the mitotic spindle, a structure that is essential for correctly distributing copied chromosomes to daughter cells. Using techniques that blend biology and chemistry, she and her colleagues are identifying molecules and proteins that play major roles in directing this dynamic cell process.