New Sub-Cellular Structure Discovered: Does It Take Two Spindles To Tango During Cell Division?

A fundamental process of cell division in plants and animals is the pulling apart and segregation of chromosomes into the two daughter nuclei, allowing genetic material to be passed on from cell to cell. Scientists have known for many years that a spindle-like structure formed by polymerized tubulin from the cytoplasm plays an important role in how this is accomplished. Now, the Iowa State team, led by Kristen Johansen, has found a new and different spindle structure made up of proteins from the nucleus.

"By using a high-resolution microscope and 3-dimensional reconstruction techniques we can see that this new nuclear scaffold is definitely a true spindle and that as best we can tell it actually is the first of the two spindle structures to form," Johansen says.

There are a lot of unknowns about how the microtubule spindle functions. For example, it is unclear how microtubules manage to pull on the chromosomes or how they align.

"Coordinated molecular interactions between the microtubule spindle and the new nuclear spindle structure have the potential to provide the answers to many of these questions," Johansen explained.

The Iowa State group, which included graduate students Diana Walker, Dong Wang, Ye Jin, Uttama Rath and Yanming Wang, as well as Jorgen Johansen, Ph.D., hopes that by better understanding the steps of normal cell division, like spindle formation, new insights will be provided into what happens during the abnormal cell divisions in cancer.

"When cancer researchers have a better understanding of how to stop cell division in cancerous cells, they could eventually develop new treatments for the disease," Johansen added.

Johansen's work was supported through a 1996 NSF CAREER award. These five-year awards are designed to offer young investigators an initial source of support for developing innovative research ideas and integrating them into their educational activities.