DURHAM, N.C. -- For centuries, scientists have watched in wonder at the microscopic world of the cell. In many ways a self-contained world, it runs much as a tiny metropolis with production plants, energy generators, and transport systems to move its products around efficiently. Now researchers are beginning to sort out just how cells get all this work done.
In a report published in the Aug. 21 issue of the journal Science, Duke cell biologist Sharyn Endow and postdoctoral fellow Kimberly Waligora said they have for the first time been able to take apart a molecular motor, put it back together, make it run in reverse, and then mutate the motor and make it run the other way.
The motor they worked on is a key component of the machinery that divides up the genetic material during a special type of cell division that makes sperm and eggs. When this machinery malfunctions, chromosomes, the carriers of genetic material, can become jumbled and the wrong number of chromosomes can end up in each egg. This can result in infertility or syndromes such as Down's, in which a child has an extra copy of chromosome 21.
The scientists hope these experimental models will give clues to why some women have multiple miscarriages, and why, as women age, more of their eggs have the wrong number of chromosomes, increasing the odds of Down's syndrome and other birth defects.
Endow discovered the motor, called Ncd (nonclaret disjunctional), in fruit flies, but similar motors operate in all animals, including people, she said.
"Our hope is that by understanding how these molecular motors operate,
we will be able to identify why sometimes things go wrong in the reproductive
process," Endow said. "Right now it is very difficult to do these experiments
with animals more advanced than flies because they make eggs internally. That
makes it difficult to observe the process. But using flies, in which the process
is thought to be
Contact: Karyn Hede George
Duke University Medical Center