RT Journal Article SR Electronic T1 Direct control of shell regeneration by the mantle tissue in the pearl oyster Pinctada fucata via accelerating CaCO3 nucleation JF bioRxiv FD Cold Spring Harbor Laboratory SP 572024 DO 10.1101/572024 A1 Jingliang Huang A1 Yangjia Liu A1 Taifeng Jiang A1 Wentao Dong A1 Guilian Zheng A1 Liping Xie A1 Rongqing Zhang YR 2019 UL http://biorxiv.org/content/early/2019/03/09/572024.abstract AB Molluscan bivalves rapidly repair the damaged shells to prevent further injury. However, it remains unclear how this process is precisely controlled. In this study, we applied scanning electronic microscopy, transmission electronic microscopy and histochemical analysis to examine the detailed shell regeneration process of the pearl oyster Pinctada fucata. It was found that the shell damage caused the mantle tissue to retract, which resulted in dislocation of the mantle zones to their correspondingly secreted shell layers. However, the secretory repertoires of the different mantle zones remained unchanged. As a result, the dislocation of the mantle tissue dramatically affected the shell morphology, and the unusual presence of the submarginal zone on the nacreous layers caused de novo precipitation of prismatic layers on the nacreous layers. Real-time PCR revealed that the expression of the shell matrix proteins (SMPs) were significantly upregulated, which was confirmed by the thermal gravimetric analysis (TGA) of the newly formed shell. The increased matrix secretion accelerated CaCO3 nucleation thus promoting shell deposition. Taken together, our study revealed the close relationship between the physiological activities of the mantle tissue and the morphological change of the regenerated shells.