2025-08-07 カリフォルニア大学アーバイン校(UCI)
A four-panel research image shows the chiton, measuring more than 20 centimeters, in the upper left. In the middle panel on the top row to the right shows the underside of the chiton where its mouth (buccal cavity) is open, highlighting the super-hard, rock-gnawing teeth are arrayed in the chiton’s mouth (far right panel). The panel on the lower left shows the evolution of the chiton teeth from light to dark, the darker color denoting the presence of hardening iron oxide in the tooth material, the process of which is focus of this study. David Kisailus / UC Irvine
<関連情報>
- https://news.uci.edu/2025/08/07/uc-irvine-scientist-takes-a-lesson-from-ultrahard-wear-resistant-mollusk-teeth/
- https://www.science.org/doi/10.1126/science.adu0043
ラデュラ歯マトリックスタンパク質1がチトンの歯における鉄酸化物沈着を制御する Radular teeth matrix protein 1 directs iron oxide deposition in chiton teeth
Michiko Nemoto https://orcid.org/0000-0003-0551-5284, Koki Okada, Haruka Akamine, Yuki Odagaki, […] , and Akira Satoh
Science Published:7 Aug 2025
DOI:https://doi.org/10.1126/science.adu0043
Editor’s summary
The major lateral radula teeth of chitons are formed from magnetite and other biominerals in a way that makes them very hard and wear resistant. As the cusps wear out, they are replaced by newly formed teeth from behind. Nemoto et al. expanded on prior studies of these organisms by exploring the molecular mechanism of magnetite biomineralization (see the Perspective by Scheffel). The authors demonstrate that one protein, which they call radular teeth matrix protein 1 (RTMP1), controls iron oxide deposition and differs from other magnetite-precipitating proteins found in magnetotactic bacteria. —Marc S. Lavine
Abstract
Nature builds multiscale mineral structures with impressive mechanical properties through spatially and temporally orchestrated organic-mineral assembly. One example of regulated mineralization is found in hypermineralized and ultrahard magnetic teeth of chiton, which grind on rock to feed on algae. At early stages of tooth formation, iron oxide deposition is controlled using a chiton-specific radular teeth matrix protein 1 (RTMP1), which is transported into teeth through microvilli. RTMP1 spatially and temporally guides and enhances mineralization on chitinous fibers within the tooth, providing a hard, tough, and strong architecture that enables the organism to perform repetitive abrasive events to survive.
