Posted on: March 2, 2004
Scientists at the University of Southern California produce a transgenic mouse in which a particular gene-called noggin -is overexpressed in the skin. (Noggin works by suppressing the action of a protein called bone morphogenic protein, or BMP, which has a key role in a number of developmental pathways in mice and humans alike).
This mutant mouse is hairier and has larger genitals.
Because of the role that noggin appears to play in the development of integument (skin and associated features), Dr. Chuong and his USC colleagues expected to see an increase in the number of hair follicles in the skin of the genetically modified mouse. And that is, indeed, what they saw. Not only was the fur of these mice thicker, with hair follicle density increasing by as much as 80 percent in the transgenic mice, but the transgenic mice also grew more whiskers than normal mice, with several whiskers sprouting from each follicle.
That, however, was only the beginning.
The overexpression of the noggin gene also led to some unusual and unexpected changes in the mice. For instance, the meibomian glands in the eyes of the transgenic mice were transformed into follicles with small hairs "pointing inwards toward the cornea," Chuong explains. (Meibomian glands are the oil-producing glands that lubricate the eyelids in humans as well as mice; an infection in the meibomian gland is what we call a stye.)
As if hairy eyes weren't enough, the sweat glands on the footpads of the mice's paws turned into hair-sprouting follicles as well. And some of them sported misshapen claws, or were missing claws altogether.
Then, while doing physical exams on the mice, Maksim Plikus from Chuong's lab, noticed one more unusual change in the transgenic mice: Their external genitalia were significantly larger than those of normal mice.
"We now think that noggin plays a role in regulating the size of penile and clitoral tissues in mice, and that it can disrupt the balanced growth of these structures and result in their overgrowth," Chuong explains.
The changes in the genitalia aren't limited to size, however. Whereas the surface of the normal mouse penis has well-differentiated microappendages called "hairy spines," the transgenic mouse's penis is smoother, less bumpy. "We don't know whether this affects sensation," says Chuong. "But we do know that they have the ability to reproduce."
This newly made transgenic mouse shows the importance of the Noggin protein. It gives the hope taht Noggin can be potentially used to stimulate hair growth and penis enlargent in men. Based on the USC News Release
For more pictures Click Here |
|
|
|
