Essential gene for male ferti...( A gene that belongs to a family of gene...)

"This gene Fkbp6 is a member of a family of genes that have been implicated in immunosuppression and heart disease," says Dr. Josef Penninger, professor of medical biophysics and immunology at U of T and senior author of a new paper in the May 23 issue of Science. "That this gene would control male fertility was completely unexpected. We originally thought Fkbp6 was important for heart function but the only place we could find it was in sperm and oocytes."

Penninger and post-doctoral fellow Michael Crackower made the surprising discovery when they eliminated the Fkbp6 gene in genetically engineered mice. When the gene was removed, the oocytes (cells in the early phases of egg development) in female mice appeared normal but all the sperm cells in males had died, resulting in complete infertility. Penninger and Crackower realized their work bore striking similarities to some research by Japanese scientists who, over the past decade, have been studying a naturally occurring mutation in rats that also caused aspermia (lack of sperm). The U of T researchers recognized that the genetic mutation in their mice was similar to the spontaneous mutation seen in the rats.

Penninger and Crackower studied the cells and tissue and found that the mice completely lacked spermatids, the male germ cells which eventually develop into spermatozoa, an elemental part of semen. The deletion of the Fkbp6 gene was isolated as the cause for the infertility in mice.

It has been estimated that 15 per cent of couples around the world remain childless because of infertility but few genetic causes have been identified. However, Penninger says, given the mice and rat data, it would be interesting to
'"/>


22-May-2003