title: How Egg Case Proteins Can Protect Cuttlefish Offspring?
abstract: Sepia officinalis egg protection is ensured by a complex capsule produced by the female accessory genital glands and the ink bag. Our study is focused on the proteins constituting the main egg case. De novo transcriptomes from female genital glands provided essential databases for protein identification. A proteomic approach in SDS-PAGE coupled with MS unveiled a new egg case protein family: SepECPs, for Sepia officinalis Egg Case Proteins. N-glycosylation was demonstrated by PAS staining SDS-PAGE gels. These glycoproteins are mainly produced in the main nidamental glands. SepECPs share high sequence homology, especially in the signal peptide and the three cysteine-rich domains. SepECPs have a high number of cysteines, with conserved motifs involved in 3D-structure. SDS-PAGE showed that SepECPs could form dimers; this result was confirmed by TEM observations, which also revealed a protein network. This network is similar to the capsule network, and it associates these structural proteins with polysaccharides, melanin and bacteria to form a tight mesh. Its hardness and elasticity provide physical protection to the embryo. In addition, SepECPs also have bacteriostatic antimicrobial activity on GRAM- bacteria. By observing the SepECP / Vibrio aestuarianus complex in SEM, we demonstrated the ability of these proteins to agglomerate bacteria and thus inhibit their growth. These original proteins identified from the outer egg case ensure the survival of the species by providing physical and chemical protection to the embryos released in the environment without any maternal protection.
authors.affiliation: Université de Caen Basse-Normandie, F-14032, Caen, France; UMR 7208, BOREA CNRS INEE, F-14032, Caen, France.
authors.forename: Valérie
authors.initials: V
authors.lastname: Cornet
authors.affiliation: Université de Caen Basse-Normandie, F-14032, Caen, France; UMR 7208, BOREA CNRS INEE, F-14032, Caen, France; Plateforme Post-génomique PROTEOGEN, F-14032, Caen, France.
authors.forename: Joël
authors.initials: J
authors.lastname: Henry
authors.affiliation: Université de Caen Basse-Normandie, F-14032, Caen, France; CMAbio, F-14032, Caen, France.
authors.forename: Didier
authors.initials: D
authors.lastname: Goux
authors.affiliation: Université de Caen Basse-Normandie, F-14032, Caen, France.
authors.forename: Emilie
authors.initials: E
authors.lastname: Duval
authors.affiliation: Université de Caen Basse-Normandie, F-14032, Caen, France; Plateforme Post-génomique PROTEOGEN, F-14032, Caen, France.
authors.forename: Benoit
authors.initials: B
authors.lastname: Bernay
authors.affiliation: Plateforme ABiMS, Station biologique de Roscoff (UPMC-CNRS), F-29688, Roscoff, France.
authors.forename: Gildas
authors.initials: G
authors.lastname: Le Corguillé
authors.affiliation: Plateforme ABiMS, Station biologique de Roscoff (UPMC-CNRS), F-29688, Roscoff, France.
authors.forename: Erwan
authors.initials: E
authors.lastname: Corre
authors.affiliation: Université de Caen Basse-Normandie, F-14032, Caen, France; UMR 7208, BOREA CNRS INEE, F-14032, Caen, France.
authors.forename: Céline
authors.initials: C
authors.lastname: Zatylny-Gaudin
mesh_terms: D000818:Animals; D049832:Decapodiformes / Q000502:physiology*; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D010063:Ovum