The physical and cellular mechanism of structural color change in zebrafish

• 成果类型: Article
• 署名作者: Gur, Dvir; Moore, Andrew S.; Deis, Rachael; Song, Pang; Wu, Xufeng; Pinkas, Iddo; Deo, Claire; Iyer, Nirmala; Hess, Harald F.; Hammer, John A.; Lippincott-Schwartz, Jennifer
• 署名单位: Weizmann Institute of Science; Howard Hughes Medical Institute; National Institutes of Health (NIH) - USA; NIH National Heart Lung & Blood Institute (NHLBI); Weizmann Institute of Science
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-9538
• DOI: 10.1073/pnas.2308531121
• 发表日期: 2024-06-04
• 关键词: pigment granules; organelle transport; neon tetra; fish; melanophores; iridophores; aggregation; melatonin; motility; form

摘要

Many animals exhibit remarkable colors that are produced by the constructive interference of light reflected from arrays of intracellular guanine crystals. These animals can fine - tune their crystal - based structural colors to communicate with each other, regulate body temperature, and create camouflage. While it is known that these changes in color are caused by changes in the angle of the crystal arrays relative to incident light, the cellular machinery that drives color change is not understood. Here, using a combination of 3D focused ion beam scanning electron microscopy (FIB - SEM), micro - focused X - ray diffraction, superresolution fluorescence light microscopy, and pharmacological perturbations, we characterized the dynamics and 3D cellular reorganization of crystal arrays within zebrafish iridophores during norepinephrine (NE) - induced color change. We found that color change results from a coordinated 20 degrees tilting of the intracellular crystals, which alters both crystal packing and the angle at which impinging light hits the crystals. Importantly, addition of the dynein inhibitor dynapyrazole - a completely blocked this NE - induced red shift by hindering crystal dynamics upon NE addition. FIB - SEM and microtubule organizing center (MTOC) mapping showed that microtubules arise from two MTOCs located near the poles of the iridophore and run parallel to, and in between, individual crystals. This suggests that dynein drives crystal angle change in response to NE by binding to the limiting membrane surrounding individual crystals and walking toward microtubule minus ends. Finally, we found that intracellular cAMP regulates the color change process. Together, our results provide mechanistic insight into the cellular machinery that drives structural color change.