Molecular cloning and expression profiles of an insulin-like growth factor binding protein IGFBP5 in the pearl oyster, Pinctada fucata

Abstract

The insulin-like growth factor binding protein (IGFBP) family participates in transportation, localization, and biological regulation of insulin-like growth factors (IGFs). In the present study, IGFBP5 gene from the Pinctada fucata (PfIGFBP5) was cloned and characterized. The full-length cDNA sequence (1319 bp) contained an open reading frame of 399 bp encoding a predicted protein of 132 amino acids. The amino acid sequence of PfIGFBP5 included an IGF binding domain and multiple cysteine residues. The genomic sequence of PfIGFBP5 consisted of three exons and two introns. PfIGFBP5 was found to be expressed in all tissues and developmental stages investigated, although the expression level was significantly higher in the pearl sac and in trochophore larvae than in other tissues or developmental stages (P < 0.05). Expression of PfIGFBP5 was induced by notching the oyster shell margin; the gene was mainly expressed in the outer epithelium of the mantle, and to a lesser extent in the whole pearl sac, including connective tissues. These findings suggest that PfIGFBP5 is very likely to be involved in modulating biomineralization in the mantle and pearl sac of P. fucata since they are the main organs for shell or pearl formation.

Characterization of Insulin-Like Growth Factor Binding Protein-5 (IGFBP-5) Gene and Its Potential Roles in Ontogenesis in the Pacific Abalone, Haliotis discus hannai

“…In invertebrate species, several members of the IGFBP superfamily have been reported, including IGFBP-7 in fruit fly Drosophila melanogaster [ 43 ], Sa-IGFBP-7 in small abalone Haliotis diversicolor [ 32 ], Py-IGFBP in scallop Patinopecten yessoensis [ 9 ], Cq-IGFBP in red claw crayfish Cherax quadricarinatus [ 44 ], Sv-IGFBP in Eastern rock lobster Sagmariasus verreauxi [ 45 ], and Mn-IGFBP in oriental river prawn Macrobrachium nipponense [ 46 ]. The IGFBP-5 gene was cloned and characterized from Pearl oyster Pinctada fucata and referred to as Pf-IGFBP-5 [ 25 ]. To date, cloning and characterization of IGFBP-5 from H. discus hannai have not been published yet.…”

“…A similar pattern of expression was also observed for the P. fucata IGFBP [ 55 ]. Fan et al [ 25 ] reported that Pf-IGFBP-5 was expressed in all examined developmental stages with the highest level in trochophore larvae.…”

“…It has been reported that IGFBP-5 plays a role in various aspects of teleost biology, including ionic homeostasis and IGF regulation in zebrafish [ 23 ], stickleback [ 24 ], and Atlantic salmon [ 16 ]. IGFBP-5 also appears to be involved in the regulation of biomineralization in the mantle and pearl sac of pearl oysters [ 25 ].…”

“…An IGFBP gene cloned and characterized from Yesso scallop ( Patinopecten yessoensis ) [ 9 ] has been suggested to have a crucial role in scallop growth and development [ 9 ]. A full-length cDNA encoding IGFBP-5 gene was isolated and characterized from the Pinctada fucata (Pf-IGFBP-5), and the results indicated that this gene may be involved in shell formation of bivalve mollusks [ 25 ]. However, there is no report on cDNA cloning, characterization, and expression analysis of the IGFBP-5 gene in H. discus hannai .…”

Growth in pearl oysters: A review of genetic and environmental influences

“…In Pi. fucata , IGFBP‐5 was expressed in hepatopancreas, adductor muscle, pearl sac, gill, gonad and mantle with the highest in mantle and pearl sac (Fan, Wang, Yu, & Xu, ). The high expression proposed the involvement of this gene in pearl sac formation and biomineralization of pearl oysters (Gricourt, Bonnec, Boujard, Mathieu, & Kellner, ).…”