Cloning of ovocalyxin-36, a novel chicken eggshell protein related to lipopolysaccharide-binding proteins, bactericidal permeability-increasing proteins, and plunc family proteins.

TitleCloning of ovocalyxin-36, a novel chicken eggshell protein related to lipopolysaccharide-binding proteins, bactericidal permeability-increasing proteins, and plunc family proteins.
Publication TypeJournal Article
Year of Publication2007
AuthorsGautron, J, Murayama, E, Vignal, A, Morisson, M, McKee, MD, Réhault, S, Labas, V, Belghazi, M, Vidal, M-L, Nys, Y, Hincke, MT
JournalJ Biol Chem
Volume282
Issue8
Pagination5273-86
Date Published2007 Feb 23
ISSN0021-9258
KeywordsAcute-Phase Proteins, Animals, Antimicrobial Cationic Peptides, Avian Proteins, Base Sequence, Blood Proteins, Calcification, Physiologic, Carrier Proteins, Chickens, DNA, Complementary, Egg Proteins, Female, Glycoproteins, Humans, Immunity, Innate, Membrane Glycoproteins, Membrane Proteins, Molecular Sequence Data, Oviducts, Phosphoproteins, Sequence Homology, Amino Acid
Abstract

The avian eggshell is a composite biomaterial composed of noncalcifying eggshell membranes and the overlying calcified shell matrix. The shell is deposited in a uterine fluid where the concentration of different protein species varies at different stages of its formation. The role of avian eggshell proteins during shell formation remains poorly understood, and we have sought to identify and characterize the individual components in order to gain insight into their function during elaboration of the eggshell. In this study, we have used direct sequencing, immunochemistry, expression screening, and EST data base mining to clone and characterize a 1995-bp full-length cDNA sequence corresponding to a novel chicken eggshell protein that we have named Ovocalyxin-36 (OCX-36). Ovocalyxin-36 protein was only detected in the regions of the oviduct where egg-shell formation takes place; uterine OCX-36 message was strongly up-regulated during eggshell calcification. OCX-36 localized to the calcified eggshell predominantly in the inner part of the shell, and to the shell membranes. BlastN data base searching indicates that there is no mammalian version of OCX-36; however, the protein sequence is 20-25% homologous to proteins associated with the innate immune response as follows: lipopolysaccharide-binding proteins, bactericidal permeability-increasing proteins, and Plunc family proteins. Moreover, the genomic organization of these proteins and OCX-36 appears to be highly conserved. These observations suggest that OCX-36 is a novel and specific chicken eggshell protein related to the superfamily of lipopolysaccharide-binding proteins/bactericidal permeability-increasing proteins and Plunc proteins. OCX-36 may therefore participate in natural defense mechanisms that keep the egg free of pathogens.

DOI10.1074/jbc.M610294200
Alternate JournalJ. Biol. Chem.
PubMed ID17179153