How Marine Bristle Worms Use a Special Protein to Distinguish Between Sunlight and Moonlight; Researcchers Gain Key Insights into Cryptochrome Protein Involved in Synchronization of Marine Organisms’ Inner Lunar Calendar with Moon Phases

In an October 30, 2023 publication in Nature Communications, a joint research team of researchers from Johannes Gutenberg University Mainz (JGU), the University of Cologne, and the University of Oldenburg has presented its findings on the functioning of an atypical cryptochrome protein (Cry). These proteins are found in a variety of organisms, and they are often involved in light-controlled biological processes. The marine bristle worm Platynereis dumerilii, for example, employs a special Cry protein designated L-Cry to distinguish between sunlight and moonlight as well as between different moon phases. This is essential for the worms to synchronize their reproduction to the full moon phase via an inner monthly calendar, also called circalunar clock. The researchers in Cologne used the cryo-electron microscopy platform of their university to visualize the three-dimensional structure of the L-Cry protein under different light conditions. The results of these structural analyses together with those of the biochemical investigations undertaken primarily at Mainz University revealed that, in the dark, L-Cry adopts a so-called dimer arrangement consisting of two subunits linked by a stable connection, while under intensive sunlight-like illumination it disassembles into its subunits or monomers. The open-access article is titled “A Marine Cryptochrome with an Inverse Photo-Oligomerization Mechanism.”