Cloning and characterization of an mRNA encoding F1-ATPase beta-subunit abundant in epithelial cells of mantle and gill of pearl oyster, pinctada fucata

In oyster biomineralization, large amounts of calcium are absorbed from external media, transported to the mineralization site, and finally deposited via a matrix-mediated process. All these activities are very energy intensive; therefore, investigations of the energy metabolism pathways of different oyster tissues will facilitate understanding of oyster biomineralization physiology. A full-length cDNA encoding the F
1
ATPase beta-subunit (the F
1
-β-subunit, a major calalytic subunit of F-ATPase) from the pearl oyster (Pinc­ tada fucata) was cloned using the homology strategy with a pair of degenerated primers based on the conserved regions of other animals' F
1
-β-subunit genes. Sequencing and structural analyses showed that the obtained sequence shared high identity with other animals' F
1
-β-subunits, and had a unique phosphorylation site of PKC and CK lion the external surface of the putative protein. Results from semi-quantitative reverse transcription-polymerase chain reaction and in situ hybridization demonstrated this oyster F
1
-β-subunit mRNA is abundant in the gill and mantle, and distributed widely in the periostracal groove, the outer folder, and the dorsal region of the mantle and in the gill epithelial cells. These tissues were the main regions that participate in biomineralization processes such as calcium uptake, transport, and matrix secretion. The results indicate that tissues involved in biomineralization have stronger energy metabolic processes and that F1-ATPase might play an important role in oyster biomineralization by providing energy transport.