Satoru OKUDA and colleagues at Kyoto University’s Virus and Regenerative Medicine Research Institute have elucidated the mechanism by which the form of eye balls is shaped. First, myosin gathers on the inner surface of nerve tissue that protrudes from the brain, and the inner surface is contracted. Next, the distal end of the protruding tissue differentiates into retinal tissue, and the function of myosin is weakened, allowing retinal tissue to enter the inside. During this spontaneous entry of retinal tissue, cells at the boundary between retinal tissue and the surrounding retinal pigmented epithelium (the edge of the cup) are forcibly bent. Cells at this boundary sense this mechanical force and actively contract along the thickness direction as a trigger to push the retinal tissue further inward. Thus, the boundary cells fine-tune their round shapes while feeling the degree of deformation of the whole eye cup tissue through mechanical force. Understanding and manipulating the shaping of organs in test tubes is important for controlling the three-dimensional shape of cell organizations used for regenerative medicine.

JST news release, November 22, 2018