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: Deciding on a purchase: Does it matter if you look up or down while shopping?

add to favorites email to friend print save as pdf

Related Stories

Korean tech start-ups offer life beyond Samsung

Feb 23, 2015

As an engineering major at Seoul's Yonsei University, Yoon Ja-Young was perfectly poised to follow the secure, lucrative and socially prized career path long-favoured by South Korea's elite graduates.

Fresh nuclear leak detected at Fukushima plant

Feb 22, 2015

Sensors at the Fukushima nuclear plant have detected a fresh leak of highly radioactive water to the sea, the plant's operator announced Sunday, highlighting difficulties in decommissioning the crippled plant.

Spacewalking astronauts route cable in 1st of 3 jobs

Feb 22, 2015

(AP)—Spacewalking astronauts routed more than 300 feet (90 meters) of cable outside the International Space Station on Saturday, tricky and tiring advance work for the arrival of new American-made crew ...

Recommended for you

Professor analyzes role of trade sanctions against Iran

10 hours ago

Israeli Prime Minister Benjamin Netanyahu addressed Congress on Tuesday as about 50 Democratic lawmakers threatened to boycott the address, offering the latest and one of the most clear microcosms of the debate about Iran's ...

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.