Molecular cloning and expression analysis of vitellogenin in scallop, Patinopecten yessoensis (bivalvia, mollusca)

Abstract

The present study was undertaken to determine scallop vitellogenin (Vtg) cDNA sequence, to identify Vtg synthesizing cell, and to analyze the regulation of Vtg mRNA expression. Clones containing partial cDNA sequence of Vtg were isolated from cDNA library of the scallop ovary by immunoscreening with the anti-scallop vitellin (Vn) serum. The deduced amino acid sequence of the clone containing the longest cDNA insert (1,689 bp) was identified as a member of the lipid transport protein family and exhibited about 20-35% identity with Vtgs of other oviparous animals. Northern blot analysis identified a single transcript longer than 10 kb in the ovary. Dot blot analysis of the ovary showed a high amount of Vtg mRNA during the growing stage and the level was retained until spawning stage. In situ hybridization demonstrated the expression of Vtg mRNA in the auxiliary cells closely associated with growing oocytes, suggesting that the synthesis of a major yolk protein in the scallop occurs through hetero-synthetic pathway without mediation through the blood flow but occurs de novo in the ovary. The content of Vtg mRNA in the ovarian tissue cultured in vitro with vitellogenesis promoting factor (VPF), which strongly promotes Vtg protein synthesis, from the cerebral plus pedal ganglion (CPG) showed no change. The transcription of Vtg mRNA appeared to be promoted by estradiol-17beta (E2) not by VPF although VPF may enhance the translation of Vtg mRNA.

Interspecific variability of endocrine disruption and oxidative stress in two bivalve species from the Ria Formosa Lagoon (south coast of Portugal)

“…In this study, neither mussels nor clams exhibited significant differences in the ALP concentrations between genders, conversely to the main idea that vitellogenin is produced specifically in females, as shown for vitellogenin protein and gene expression in other bivalves (Osada et al 2004). Seasonal studies using different bivalve molluscs have shown that ALP levels follow the same trend as the gametogenic cycle in females, with mature individuals having naturally higher ALP concentrations.…”

Interspecies comparison of selected pollution biomarkers in dreissenid spp. inhabiting pristine and moderately polluted sites

“…In mature females, Vtg are generally synthesized in response to endogenous estrogens, such as 17ß-estradiol (E2), released into the bloodstream and then stored in developing oocytes. Studies have outlined that levels of E2 in molluscs display a seasonal alternation associated with the reproductive cycle and are synchronized with variations of oocyte diameter and assumed Vitellogenin mRNA levels from early vitellogenic stage to spawning stage (Matsumoto et al, 1997(Matsumoto et al, , 2003Osada et al, 2004;Ni et al, 2014). Ni et al (2014) in their study recorded several magnitude higher vitellogenins expression in the ovary of C. gigas in the maturation and ripeness stages than in the partially spent stage.…”

Development of EST-SSRs in scallop (Patinopecten yessoensis) from sequence database

“…But there are only a few studies about genetic diversity of P. yessoensis species at DNA levels thus far, and the documents about P. yessoensis mostly focused on the molecular clone of P. yessoensis (Osada et al 2004;Sato and Nagashima 2001) and protein analyze (Sarashina and Endo 2001;Kim et al 2008).…”