Division of Molecular and Developmental Biology • Kawakami Group

The lateral line system of teleost fish is composed of mechanosensory receptors (neuromasts), some of which are superficial whereas others are embedded in canals running under the skin. Canal diameter and size of canal neuromasts are correlated with increasing body size, thus providing a very simple system to investigate the mechanism underlying the coordination between organ growth and body size. Here, we examine the development of the trunk lateral line canal system in zebrafish. We demonstrate that trunk canals originate from scales through a bone remodeling process. We suggest that the bone remodeling process is essential for normal growth of canals and of canal neuromasts. Moreover, we show that the presence of lateral line cells is required for the formation of canals, suggesting the existence of mutual interactions between the sensory system and surrounding connective tissues.

(A) The lateral line sense organ, the neuromast, is located on the skin surface in embryonic stages. (B) When fish undergo metamorphosis, a pair of ridges extends outward from the scale. At the same time, bony elements under the neuromast gradually disappear. (C) The neuromast becomes embedded in the canal running under the scale in adult fish.