"Not many proteins are expressed in both male and female germ lines that are specific only to the germ line," says Hecht. Germ line refers to the group of cells that give rise to either sperm or eggs in animals, as opposed to all other cell types, which are called somatic cells. "There are many proteins whose deletion will cause male infertility, and others for creating female infertility, but not many that will lead to both male and female infertility without affecting the somatic cells."
Animals deficient in the protein called MSY2 are infertile, but are otherwise healthy and completely normal. Male mice produce no functional sperm, and females show early loss of eggs and defects in ovulation.
The MSY2 protein is part of a family of proteins, called Y-box proteins, that are present in most organisms, ranging from bacteria to humans. In the nuclei of developing germ cells, MSY2 enhances synthesis of a select group of messenger RNA (mRNA) molecules and transports them from the nucleus into the cytoplasm. There, MSY2 proteins stabilize the mRNAs, which are used to make new proteins. Many of these proteins are critical for the production of normal sperm and also are unique to germ cells.
"When trying to develop a new contraceptive, it's hard because we need to identify a target that's specific to the germ cells," says Hecht. "Clearly, if we inactivate the function of a pr
Contact: Karen Kreeger
University of Pennsylvania School of Medicine