The Role of Matrix Proteins in Eggshell Formation

In this article we review the results of recent proteomic, transcriptomic and genomic analyses of the eggshell constituents and draw attention to the impact of this data on current understanding of eggshell mineralization. The most abundant constituents of the chicken eggshell have been identified. An exciting new approach is to determine which genes are upregulated during the onset of mineralization. New information from studies with purified native or recombinant eggshell proteins are necessary for in vitro tests to gain insight into the role of each isolated matrix component, and eventually to learn how they may function synergistically. One important goal will be to determine the impact and importance of posttranslational modification of matrix components (glycosylation, glycanation, phosphorylation, etc.), which could greatly alter their properties and interactions. These investigations will continue to provide new insights into function of integrated defense strategies that operate at biomineralized barriers. Genes involved in the physical or chemical defense of the egg are functional candidates for marker assisted selection to improve egg and eggshell quality.