Making Connections

Every hectic household needs a bulletin board. Members of the family can communicate with one another in one common place. They always know where to go when they need information. ASU cell biologists say that is idea is true even when the “household” is a tiny egg cell.

Dave Capco and Page Baluch believe that egg cells use a structure called the meiotic spindle as a “bulletin board” for communication upon fertilization. To learn more, they study mouse eggs at an single point during the process of cell division, or meiosis.

The meiotic spindle holds DNA in place. When the egg cell is fertilized, it ejects half the DNA and takes half from the sperm cell. Capco and Baluch compare the spindle to scaffolding.

“There are enzymes hanging on to the scaffolds, like the last tower from Ground Zero in New York, where people had placed pictures and notes. It’s a centralized area of communication that keeps it from diffusing,” says Capco, an ASU biology professor.

To study the spindle and the enzymes attached, the researchers use a laser scanning confocal microscope. They use antibodies to “stain” certain target materials, such as tubulin, which makes up the spindle structure.

“The antibody binds to the things we want to highlight. The laser hits the antibody and excites it. When excited, the antibody emits light,” says Baluch. The light creates an image of the material being observed.

The problem with light is that it scatters, producing a blurry image. To see more detail, scientists need a way to filter the scattered light. Enter the PRISM team.

“The computer scientists realized this is actually digital data. They applied algorithms to reduce the scatter and produced more detailed images of the tubules of the spindles,” says Baluch, a doctoral student in biology.

Jiuxiang Hu is a PRISM post-doctoral researcher. He developed algorithms to sharpen the images and applied new techniques for extracting shapes or features of interest. With these improved 3D images, the researchers are gathering new information about the meiotic spindle. For example, they are now able to discover distinct patterns among the enzymes clinging to the spindle.

“With the confocal image, you can tell it’s there, but this program shows patterns of where,” says Baluch.

She adds that the research could be useful in improving the transfer of cell nuclei during cloning experiments.

“Currently, scientists take an egg in arrest and remove the spindle, replacing it with the somatic DNA. It’s not highly successful. Maybe part of the reason is that they just insert the DNA. There is no scaffolding for communication.”—Diane Boudreau