Characterization of a novel carbonic anhydrase from freshwater pearl mussel Hyriopsis cumingii and the expression profile of its transcript in response to environmental conditions

• We characterized a novel α-carbonic anhydrase (HcCA) gene form Hyriopsis cumingii.
• Expression of HcCA is significantly regulated by environmental factors.
• HcCA plays a role in the shell growth and pH homeostasis of H. cumingii.

Gene encoding for α-carbonic anhydrases (α-CAs) and their functions in fundamental metabolism and biomineralization are widely identified in mollusks. However, the transcriptional regulation of α-CA genes in response to various environmental conditions remains unknown. In the present study, we characterized a cDNA encoding for an α-CA (HcCA) from the freshwater pearl mussel Hyriopsis cumingii. The spatial and temporal expression patterns of HcCA indicate that this gene is mainly expressed in the mantle of juvenile mussels. The expression profile of HcCA under various environmental conditions reveals that the transcription of HcCA is significantly regulated by Ca2 + concentration, water temperature, pH and air exposure. Our results suggest that HcCA is a crucial target gene by which the external environmental conditions affecting shell growth and pH homeostasis of H. cumingii.