Pancreatic lipase-related protein (PY-PLRP) highly expressed in the vitellogenic ovary of the scallop, Patinopecten yessoensis

A cDNA (1206 bp) encoding a pancreatic lipase-related protein (PY-PLRP) was obtained from the ovary of the scallop, Patinopecten yessoensis, using a differentially expressed gene system. The open reading frame specified a protein containing 353 amino acids (~ 38 kDa). The N-terminal catalytic domain, which contained the catalytic triad of serine, aspartate, and histidine residues, 10 cysteine residues involved in disulfide bridges, and the conserved lid domain, indicated that the protein would be catalytically active. However, PY-PLRP lacked the C-terminal colipase-binding domain present in mammalian PLRPs. Sequence analysis of the catalytic domains of PY-PLRP with members of the pancreatic triglyceride lipase (PTL) family suggested that PY-PLRP was related to mammalian PLRP1, PLRP2, and PTL. End-point reverse transcriptase-polymerase chain reaction (RT-PCR) after 25 cycles showed that PY-PLRP was expressed at a high level in the ovary and at low levels in testis and mantle; expression was not detected in gill, digestive gland, and adductor muscle. Quantitative PCR of RNA from ovaries at different stages of development showed that PY-PLRP was expressed at a significantly higher level in the late growth stage than in the ripe and spent stages. These data suggest that PY-PLRP plays a role in lipid metabolism associated with oocyte maturation and vitellogenesis that occurs during ovarian growth.