Now hear this

 作者:荀啄锼     |      日期:2019-03-08 02:13:17
By Jonathan Knight THE same pair of proteins choreographs the development of bristles on flies and hairs in the human inner ear. This finding could eventually lead to treatments for hearing loss, say biologists. Fruit flies do not have ears, but detect sound vibrations using stiff bristles that cover most of their bodies. Two proteins, called notch and jagged, help arrange the bristles on the developing fly into a fixed pattern. Matthew Kelley of Georgetown University in Washington DC suspected the same protein duo might be at work in the cochlea—the mammalian inner ear—which also has a regular arrangement of sensory hairs. “This is one of the few examples of a precise pattern in mammals,” he says. Kelley and his colleagues stained cochleae from mice at different stages of development to reveal which cells had the genes for notch and jagged turned on. In the early stages, when all cochlea cells were identical, all expressed notch. Later jagged appeared, but only in cells destined to become hair cells ( Nature Genetics, vol 21, p 289). Work on flies had already shown that notch is a cell surface receptor to which jagged can bind. Kelley believes that hair cells probably secrete jagged to tell their neighbours to become support cells instead. This keeps the pattern in the cochlea regular. “When you need to make a precise cellular pattern in any animal, you’re going to use this system,