Journal Article

How Egg Case Proteins Can Protect Cuttlefish Offspring?

Cornet, Valérie, Bernay, Benoit, Zatylny-Gaudin, Céline, Corre, Erwan, Henry, Joël, Goux, Didier, Duval, Emilie, Le Corguillé, Gildas

2015

Overview

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.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Animal behavior / Animal biology / Animals / Antimicrobial activity / Antimicrobial agents / Aplysia / Bacteria / Bacterial infections / Collagen / Decapodiformes - physiology / Development Biology / Dimers / Eggs / Elasticity / Electrophoresis, Polyacrylamide Gel / Embryology and Organogenesis / Embryonic development / Embryos / Female / Gel electrophoresis / Gels / Glands / Glycoproteins / Glycosylation / Gram-negative bacteria / Homology / Internet / Invertebrate Zoology / Keratin / Life Sciences / Melanin / Microscopy, Electron, Scanning / Microscopy, Electron, Transmission / Molecular structure / Morphology / Next-generation sequencing / Offspring / Ovum / Pheromones / Polysaccharides / Proteins / Proteomics / Reproductive Biology / Saccharides / Sepia officinalis / Sexual reproduction / Sodium lauryl sulfate / Squalus acanthias / Structural proteins / Studies / Waterborne diseases