Hen uterine gene expression profiling during eggshell formation reveals putative proteins involved in the supply of minerals or in the shell mineralization process

Abstract

BackgroundThe chicken eggshell is a natural mechanical barrier to protect egg components from physical damage and microbial penetration. Its integrity and strength is critical for the development of the embryo or to ensure for consumers a table egg free of pathogens. This study compared global gene expression in laying hen uterus in the presence or absence of shell calcification in order to characterize gene products involved in the supply of minerals and / or the shell biomineralization process.ResultsMicroarrays were used to identify a repertoire of 302 over-expressed genes during shell calcification. GO terms enrichment was performed to provide a global interpretation of the functions of the over-expressed genes, and revealed that the most over-represented proteins are related to reproductive functions. Our analysis identified 16 gene products encoding proteins involved in mineral supply, and allowed updating of the general model describing uterine ion transporters during eggshell calcification. A list of 57 proteins potentially secreted into the uterine fluid to be active in the mineralization process was also established. They were classified according to their potential functions (biomineralization, proteoglycans, molecular chaperone, antimicrobials and proteases/antiproteases).ConclusionsOur study provides detailed descriptions of genes and corresponding proteins over-expressed when the shell is mineralizing. Some of these proteins involved in the supply of minerals and influencing the shell fabric to protect the egg contents are potentially useful biological markers for the genetic improvement of eggshell quality.

Quantitative proteomics provides new insights into chicken eggshell matrix protein functions during the primary events of mineralisation and the active calcification phase

“…We also identified carbonic anhydrase II (CA2) in this group, an enzyme which catalyses the conversion of carbon dioxide in bicarbonate ions using water molecules [34]. Therefore, this enzyme might supply bicarbonate ions from uterus cells to the lumen then transform bicarbonate to carbonate during the mineralisation process to form the calcium carbonate [35,36].…”

Eggshell structure, measurements, and quality-affecting factors in laying hens: a review

“…The second group consists of proteins that are widely found in various organs and biological fluids. This group includes osteopontin (a phosphorylated glycoprotein of bone, kidney and present in various body secretions and also in the core of the non-mineralized shell membrane fibres, and in the outermost part of the palisade layer of the chicken eggshell) and clusterin, a widely distributed secretory glycoprotein also present in the egg white (Brionne et al 2014;Gautron et al 2014). The third group is named eggshell-specific proteins because they were identified during the investigation of abundant constituents of the eggshell and uterine fluid.…”

Dietary calcium deficiency in laying ducks impairs eggshell quality by suppressing the process of shell biomineralization

“…OPN localizes specifically in the palisade and mammillae layers (mammillary cores) of the shell (Fernandez et al, 2003;Chien et al, 2008). Its gene expression in the uterus of chicken is stimulated by the presence of the egg in the uterus (Lavelin et al, 2000;Brionne et al, 2014) or due to mechanical distension of the uterine wall (Lavelin et al, 1998). These observations indicate the importance of OPN in shell calcification.…”

“…More than 500 proteins have been identified in the chicken eggshell proteome (Mann et al, 2006). The occurrence of some of these matrix proteins in the uterus coincides with the concomitant presence of the egg in each uterine region (Lavelin et al, 1998(Lavelin et al, , 2000Brionne et al, 2014), suggesting an important role for the matrix protein in the control of eggshell calcification.…”