title: Egg serpins: The chicken and/or the egg dilemma.
abstract: Twenty-seven serpins belonging to clade A, B, C, D, E, F, G, H and I serpins are currently referenced in chicken genome databases. Phylogenetic analysis of chicken serpins revealed that ovalbumin (Serpinb14) and its paralogs ovalbumin-related protein Y (Serpinb14b) and ovalbumin-related protein X (Serpinb14c) are found in bird species. These clade B serpins are specifically expressed in reproductive tissues and exported in the egg where they constitute major protein components. These data suggest that these three paralogs have probably appeared in birds to face new environments and ensure the extra-uterine development of an embryo in a shell egg. Twelve other serpins have been identified in the newly produced egg, some of them having a specific distribution in the respective egg structures (eggshell, egg white, vitelline membrane and egg yolk). The physiological role of these egg serpins remain largely unexplored, but there is increasing evidence in literature or by homologies with their mammalian counterparts, that some of them participate in cell proliferation, tissue remodeling and/or angiogenesis associated with folliculogenesis and development of extraembryonic structures, eggshell biomineralization, egg defense and nutrition of the embryo. A better knowledge of the phylogenetic evolution of these 15 serpins in other oviparous species, on their egg distribution, on their regulation during embryonic development (activation/degradation/transfer) and on their functional specificity, is needed to better appreciate their role and their bird-specificity. These review shed light on the multiple possibilities that offer the avian egg model to study the role of serpins in reproduction and developmental biology.
authors: INRA, UMR85 Physiologie de la Reproduction et des Comportements, F-37380 Nouzilly, France; CNRS, UMR6175 Physiologie de la Reproduction et des Comportements, F-37380 Nouzilly, France; Université François Rabelais de Tours, F-37041 Tours, France; IFCE, F-37380 Nouzilly, France.
authors: Clara
authors: C
authors: Dombre
authors: INRA, UR83 Recherches Avicoles, F-37380 Nouzilly, France.
authors: Nicolas
authors: N
authors: Guyot
authors: CEPR, UMR INSERM U1100, Faculté de Médecine, Université de Tours, 10 Bd. Tonnellé, F-37032 Tours Cedex, France.
authors: Thierry
authors: T
authors: Moreau
authors: INRA, UMR85 Physiologie de la Reproduction et des Comportements, F-37380 Nouzilly, France; CNRS, UMR6175 Physiologie de la Reproduction et des Comportements, F-37380 Nouzilly, France; Université François Rabelais de Tours, F-37041 Tours, France; IFCE, F-37380 Nouzilly, France.
authors: Philippe
authors: P
authors: Monget
authors: INRA, UR83 Recherches Avicoles, F-37380 Nouzilly, France.
authors: Mylène
authors: M
authors: Da Silva
authors: INRA, UR83 Recherches Avicoles, F-37380 Nouzilly, France.
authors: Joël
authors: J
authors: Gautron
authors: INRA, UR83 Recherches Avicoles, F-37380 Nouzilly, France. Electronic address: srehault@tours.inra.fr.
authors: Sophie
authors: S
authors: Réhault-Godbert
mesh_terms: D000818:Animals; D002645:Chickens / Q000378:metabolism*; D019143:Evolution, Molecular; D008958:Models, Molecular; D010063:Ovum / Q000378:metabolism* / Q000648:ultrastructure; D010802:Phylogeny; D015843:Serpins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D015843:Serpins
keywords: Birds; Development; Egg formation; Reproduction; Serpins