( Human eggs rely on handmaidens. Called ...)A surprising pair of proteins help make healthy eggs

How do these handmaidens grow? Biologists at Brown University and the University of California–Berkeley have discovered that two proteins ?TAF4b and c-Jun ?team up to turn on about two dozen genes inside the nuclei of granulosa cells. This subset of genes, in turn, writes the genetic code for proteins that cause granulosa cells to multiply and nurture developing eggs.

The finding, published in an advanced online edition of the Proceedings of the National Academy of Sciences, provides an important piece of the reproduction puzzle, and it points to possible drug targets for treating infertility and ovarian cancer.

"Thousands of women in this country undergo fertility treatments each year and some have no idea why they can't get pregnant," said Richard Freiman, an assistant professor in the Department of Molecular Biology, Cell Biology and Biochemistry at Brown. "This research gives us important new information about fertility. It's a basic science finding, but it may provide answers for some of these women and, possibly, lead to better in-vitro fertilization therapies."

In 2001, Freiman and colleagues at Berkeley published a paper in Science describing the essential role a transcription factor called TAF4b plays in the fertility of female mice. Without this protein, egg-producing ovarian follicles didn't develop properly. The result: infertile mice.

The new research underscores TAF4b's central role in normal reproduction. The Brown and Berkeley team found that in the granulosa cells of the ovary, it triggers production of another protein, called c-Jun, and together they switch on a network of ovarian genes that help promote granulosa cell proliferation.

"The big surprise was c-Jun," Freiman said.

That's because this well-studied p
'"/>

Source:Brown University