The mantle exosome proteins of Hyriopsis cumingii participate in shell and nacre color formation.

Pearl color is closely related to the nacre color of shell in Hyriopsis cumingii , and pearl color has a huge impact on its price. The nacre is an important part of the shell, and studies have suggested that mantle exosomes participated in shell formation. Exosomes contain many different proteins that are involved in different biological processes. In this study, exosomes were extracted from mantles of mussels with different nacre color. TMT quantitative proteome sequencing analysis was performed on purple and white mussel mantle exosomes, and 4861 proteins were obtained. Based on the standard of (|log2 (Fold change)| ≥ 1.2 or ≤ 0.83 and p -value ≤ 0.05), a total of 758 differentially expressed proteins were found. Some proteins involved in shell and nacre color formation were predicted with the proteins annotate, GO classification system. Moreover, 14 differentially expressed proteins (including eight up-regulated proteins and six down-regulated proteins) were validated using parallel reaction monitoring (PRM) assays. Overall, this information will be useful to improve our understanding of the molecular mechanisms of shell and nacre color formation in H. cumingii. Mantle epidermis absorb Ca²⁺, metal ions and nutriments from the living water environment, which are transported by blood or other mechanisms into the mantle and secreted by epithelial cells between the hemolymph and mantle cavity. Final calcification occurs in the mantle cavity and is deposited on the shell. Exosomes as a secretion may play an important role in the formation of shell and nacre color. [Display omitted] • We extracted exosomes from the mantle of white and purple mussels in H. cumingii. • A large number of proteins were identified. • Some proteins that affect shell structure were found. • Metal ion-related proteins affect nacre color formation. [ABSTRACT FROM AUTHOR]