Mechanism regulating tooth shape formulation found

Sep 23, 2005

One of the remaining challenges for evolutionary developmental studies of mammals, whose evolution is best known from their teeth, is how their tooth shape is altered during development.

Researchers of the University of Helsinki together with their Japanese colleagues from the University of Kioto now propose a 'balance of induction' mechanism directing the placement of tooth shape features called cusps. Position and shape of cusps determine whether a tooth shape belongs to human or mouse, for example. Whereas developmental initiation of cusp formation is known to involve several developmental genes at the places of future cusps, it has remained unknown how cusps form at the right places.

Computer simulations on tooth development have suggested that there should be a gene inhibiting induction of cusps. The research team has now identified this inhibitor to be a recently identified gene called ectodin. It turned out that ectodin is the first gene that is expressed as a mirror image of the future cusps.

The team generated a mouse that has no functional ectodin. Whereas the mice appear fairly normal, the areas forming cusps were much broader resulting in cheek teeth whose shape resembles more rhinoceros teeth than mouse teeth. Furthermore, these mice have extra teeth and sometimes adjacent teeth are fused. These results indicate that there is a delicate balance of induction and inhibition in determining tooth cusps and that ectodin is a key gene in this developmental control.

The team confirmed the importasnce of ectodin to development of teeth by culturing teeth that produce ectodin and teeth that lack ectodin with excess amounts of cusp inducing protein (bone morphogenetic protein or BMP). Whereas teeth producing ectodin develop quite normally with excess BMP, teeth without ectodin had a markedly accelerated induction of cusps. Indeed the researchers were able to induce cusps and mineralization of teeth much faster than happens in normal mouse teeth, suggesting that tinkering with the balance of cusp induction may hold potential for future tissue engineering of hard tissues.

Source: University of Helsinki

Explore further: Mapping the world's linguistic diversity—scientists discover links between your genes and the language you speak

Related Stories

Learning from biology to accelerate discovery

21 minutes ago

A spider's web is one of the most intricate constructions in nature, but its precious silk has more than one use. Silk threads can be used as draglines, guidelines, anchors, pheromonal trails, nest lining, ...

Shark's unique trek could help save the species

12 hours ago

Her name is Jiffy Lube2, a relatively small shortfin mako shark that, like others of her kind, swims long distances every day in search of prey and comfortable water temperatures.

New Horizons spacecraft experiences anomaly

13 hours ago

The New Horizons spacecraft experienced an anomaly the afternoon of July 4 that led to a loss of communication with Earth. Communication has since been reestablished and the spacecraft is healthy.

Dwarf planet Ceres offers big surprises for scientists

13 hours ago

The closer we get to Ceres, the more perplexing the dwarf planet grows. NASA's Dawn spacecraft has found several more bright spots as well as a pyramid-like peak jutting out of the frigid world's surface.

Recommended for you

Lady, you're on the money

Jul 03, 2015

So far, women whose portraits appear on U.S. money have been a party of three. Excluding commemorative currency, only Sacagawea, Susan B. Anthony and Helen Keller appear on coins in general circulation, according ...

Old World monkey had tiny, complex brain

Jul 03, 2015

The brain hidden inside the oldest known Old World monkey skull has been visualized for the first time. The creature's tiny but remarkably wrinkled brain supports the idea that brain complexity can evolve ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.