This Article Full Text Full Text (PDF) All Versions of this Article: jhc.2008.950576v1 56/5/467    most recent Alert me when this article is cited Alert me if a correction is posted Citation Map Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Hincke, M. T. Articles by McKee, M. D. Search for Related Content PubMed PubMed Citation Articles by Hincke, M. T. Articles by McKee, M. D. Social Bookmarking                      What's this?

Colloidal-gold Immunocytochemical Localization of Osteopontin in Avian Eggshell Gland and Eggshell

Maxwell T. Hincke, Yung-Ching Chien, Louis C. Gerstenfeld and Marc D. McKee

Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada (MTH); Faculty of Dentistry (Y-CC,MDM) and Department of Anatomy and Cell Biology (MDM), McGill University, Montreal, Quebec, Canada; and Department of Orthopaedic Surgery, Boston University, Boston, Massachusetts (LCG)

Correspondence to: Marc D. McKee, PhD, Faculty of Dentistry, 3640 University Street, Montreal, Quebec, Canada H3A 2B2. E-mail: marc.mckee{at}mcgill.ca

During mineralization of the avian eggshell, there is a sequential and orderly deposition of both matrix and mineral phases. Therefore, the eggshell is an excellent model for studying matrix–mineral relationships and the regulation of mineralization. Osteopontin, as an inhibitor of crystal growth, potently influences the formation of calcium phosphate and calcium carbonate biominerals. The purpose of this study was to characterize matrix–mineral relationships, specifically for osteopontin, in the avian eggshell using high-resolution transmission (TEM) and scanning (SEM) electron microscopy to gain insight into how calcite crystal growth is structured and compartmentalized during eggshell mineralization. Osteopontin was localized at the ultrastructural level by colloidal-gold immunocytochemistry. In EDTA-decalcified eggshell, an extensive matrix network was observed by TEM and SEM throughout all regions and included interconnected fibrous sheets, irregularly shaped aggregates, vesicular structures, protein films, and isolated protein fibers. Osteopontin was associated with protein sheets in the highly mineralized palisades region; some of these features defined boundaries that compartmentalized different eggshell structural units. In fractured and undecalcified eggshell, osteopontin was immunolocalized on the {104} crystallographic faces of calcite—its natural cleavage plane. The specific occlusion of osteopontin into calcite during mineralization may influence eggshell structure to modify its fracture resistance. (J Histochem Cytochem 56:467–476, 2008)

Key Words: osteopontin • calcite • biomineralization • eggshell • eggshell matrix • chicken

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

Guidelines | Subscriptions | About | exPRESS - Current - Archive | Business Information | Contact

The Journal of Histochemistry & Cytochemistry is owned, published, and licensed by The Histochemical Society © 2008