Proteomic identification of quality factors for oocytes in the Pacific oyster Crassostrea gigas.

We used a 2-DE proteomic approach to identify abundant proteins linked to oocyte quality in the Pacific oyster Crassostrea gigas, an economically important bivalve. Oocyte quality of 14 females was estimated by recording fertilisation and early developmental success until D-larval stage under controlled conditions. Proteins that were differentially expressed between females showing high or low oocyte quality were identified by nano-liquid chromatography tandem mass spectrometry. Twelve up-accumulated spots associated with low quality oocytes revealed 10 distinct proteins, including vitellogenin - breakdown products and metabolic enzymes. Eight up-accumulated spots from high quality oocytes revealed 6 distinct proteins, including chaperone molecules and cell-cycle control proteins. This is the first proteomic study dedicated to oocytes in C. gigas. Our results improve current knowledge about protein factors associated with oocyte quality in this species, and our understanding of the proteomic processes involved in their developmental competence.