Characterization of GnRH-related peptides from the Pacific oyster Crassostrea gigas.
Gonadotropin-releasing hormone (GnRH), a key neuropeptide regulating reproduction in vertebrates has now been characterized in a number of non-vertebrate species. Despite the demonstration of its ancestral origin, the structure and the function of this family of peptides remain poorly known in species as distant as lophotrochozoans. In this study, two GnRH-related peptides (Cg-GnRH-a and CgGnRH-G) were characterized by mass spectrometry from extracts of the visceral ganglia of the Pacific oyster Crassostrea gigas. These peptides showed a high degree of sequence identity with GnRHs of other mollusks and annelids and to a lesser extent with those of vertebrates or with AKH and corazonins of insects. Both the mature peptides and the transcript encoding the precursor protein were exclusively expressed in the visceral ganglia. Significant differences in transcriptional activity of Cg-GnRH encoding gene were recorded in the ganglia along the reproductive cycle and according to trophic conditions with a higher level in fed animals compared to starved animals. This suggests the involvement of Cg-GnRHs as synchronizers of nutritional status with energy requirements during reproduction in oyster. Evidence for a role of Cg-GnRHs as neuroregulators and as neuroendocrine factors in bivalve is discussed.
Université de Caen Basse-Normandie, IBFA, Biologie des Mollusques marins et des Ecosystèmes Associés (BioMEA), 14032 Caen Cedex, France.
Laetitia
L
Bigot
Céline
C
Zatylny-Gaudin
Franck
F
Rodet
Benoit
B
Bernay
Pierre
P
Boudry
Pascal
P
Favrel
D000595:Amino Acid Sequence; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D049896:Crassostrea / Q000737:chemistry* / Q000502:physiology; D005260:Female; D017952:Ganglia, Invertebrate / Q000737:chemistry*; D015870:Gene Expression; D007987:Gonadotropin-Releasing Hormone / Q000737:chemistry* / Q000502:physiology; D007313:Insecta / Q000737:chemistry / Q000502:physiology; D008297:Male; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D010802:Phylogeny; D012098:Reproduction / Q000235:genetics*; D017386:Sequence Homology, Amino Acid; D013217:Starvation; D014020:Tissue Extracts / Q000737:chemistry; D014714:Vertebrates / Q000502:physiology
D014020:Tissue Extracts; D007987:Gonadotropin-Releasing Hormone