Cloning of ovocalyxin-36, a novel chicken eggshell protein related to lipopolysaccharide-binding proteins, bactericidal permeability-increasing proteins, and plunc family proteins.
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.
Gautron
Joël
J
Institut National de la Recherche Agronomique, UR83 Unité de Recherches Avicoles, F-37380 Nouzilly, France. gautron@tours.inra.fr
Murayama
Emi
E
Vignal
Alain
A
Morisson
Mireille
M
McKee
Marc D
MD
Réhault
Sophie
S
Labas
Valérie
V
Belghazi
Maya
M
Vidal
Mary-Laure
ML
Nys
Yves
Y
Hincke
Maxwell T
MT
D000209:Acute-Phase Proteins / Q000235:genetics* / Q000276:immunology; D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000235:genetics / Q000276:immunology; D030161:Avian Proteins / Q000235:genetics* / Q000276:immunology; D001483:Base Sequence; D001798:Blood Proteins / Q000235:genetics / Q000276:immunology; D002113:Calcification, Physiologic / Q000235:genetics* / Q000276:immunology; D002352:Carrier Proteins / Q000235:genetics* / Q000276:immunology; D002645:Chickens / Q000235:genetics* / Q000276:immunology; D018076:DNA, Complementary / Q000235:genetics / Q000276:immunology; D004527:Egg Proteins / Q000235:genetics* / Q000276:immunology; D005260:Female; D006023:Glycoproteins / Q000235:genetics / Q000276:immunology; D006801:Humans; D007113:Immunity, Innate / Q000235:genetics*; D008562:Membrane Glycoproteins / Q000235:genetics* / Q000276:immunology; D008565:Membrane Proteins / Q000235:genetics / Q000276:immunology; D008969:Molecular Sequence Data; D010057:Oviducts / Q000276:immunology; D010750:Phosphoproteins / Q000235:genetics / Q000276:immunology; D017386:Sequence Homology, Amino Acid; D000099231:Lipopolysaccharide-Binding Protein
D000209:Acute-Phase Proteins; D023181:Antimicrobial Cationic Peptides; D030161:Avian Proteins; D001798:Blood Proteins; D002352:Carrier Proteins; D018076:DNA, Complementary; D004527:Egg Proteins; D006023:Glycoproteins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D010750:Phosphoproteins; D000099231:Lipopolysaccharide-Binding Protein; C485599:BPIFA1 protein, human; C021623:bactericidal permeability increasing protein