Identification of Ras, Pten and p70S6K homologs in the Pacific oyster Crassostrea gigas and diet control of insulin pathway

Functional characterization of a short neuropeptide F-related receptor in a Lophotrochozoa, the mollusk Crassostrea gigas

“…This is especially true during gametogenesis, a period of negative energy budget (Soletchnik et al, 1997) that appears to be genetically correlated with susceptibility to summer mortality (Huvet et al, 2010), which is one of the current major burdens of oyster aquaculture. A variety of neuroendocrine signaling pathways operate to cope with these constraints, of which some have already been identified in the oyster (Bigot et al, 2012) (Jouaux et al, 2012). Our results on the characterization of an oyster Cg-sNPF-like receptor provide insights into novel neuroendocrine pathways regulating key …”

“…Here, sNPF signaling affects growth and carbohydrate levels by controlling insulin signaling (Lee et al, 2008). Given the recent findings that insulin signaling responds to nutrient levels in the C. gigas gonad (Jouaux et al, 2012), and the control of insulin producing cells by LFRFamide peptides in L. stagnalis (Hoek et al, 2005), it is conceivable to consider that mollusk LFRFamide peptides represent functional analogues of arthropod sNPFs.…”

Sex-Specific Regulation of AMP-Activated Protein Kinase (AMPK) in the Pacific Oyster Crassostrea gigas1

“…An increase in 17b-estradiol has been observed during gametogenesis, suggesting its role in vitellogenesis [14], and an estrogen receptor is predominantly expressed in mature animals [15]. Moreover, several elements of the insulin signaling pathway were identified in C. gigas: an insulin-like peptide ligand (ILP) expressed in the visceral ganglia and regulated during gametogenesis [16], a C. gigas insulin receptor-related receptor (CIR) [17], Ras oncogene, phosphatase-tensin homolog deleted on chromosome (PTEN), and p70-S6 kinase [18]. However, no functional data are yet available for these endocrine and signaling molecules in reproduction, and further analyses are needed to study their function.…”

“…When these signaling pathways are deregulated, animals are less fertile [28,29]. In the past, gonad differentiation and development in oysters were studied by measuring the expression of genes potentially involved in reproduction (for example, CG-FOXL2 [30,31], CG-DML [32], vasa (termed oyvlg) [5], or OG-TGF beta [33,34]) or elements belonging to the insulin pathway [16][17][18], and recently by a genome-wide expression profiling that identified gonad-and sex-specific genes and potential markers of early sex differentiation in C. gigas [35]. Despite this work, however, our understanding of the mechanisms of the regulation of gonad development versus storage tissue is still limited [36].…”

Additive transcriptomic variation associated with reproductive traits suggest local adaptation in a recently settled population of the Pacific oyster, Crassostrea gigas

“…In C. gigas, an Insulin-related peptide receptor has previously been identified in oysters by Gricourt et al [67] as well as several factors of the insulin signalling pathway. Jouaux et al [68] found that insulin pathway elements can modulate germinal cells proliferation during food deprivation in the first stages of gametogenesis with expected consequences on fertility.…”