title: Mechanical strain regulation of the chicken glypican-4 gene expression in the avian eggshell gland.
abstract: Comparison of RNA fingerprinting of the avian eggshell gland (ESG) without and with an egg revealed upregulation of a 382-bp cDNA fragment that showed high homology to the mammalian glypican 4 (GPC-4). The gene sequence revealed a conserved glypican signature, a glycosyl phosphatidyl inositol-anchorage site, and cystein residues, most of which were conserved. GPC-4 was expressed in the ESG in a circadian fashion only during the period of eggshell calcification, when maximal mechanical strain was imposed. Removal of the egg just before to its entry into the ESG, with consequent elimination of the mechanical strain, caused reduction in the gene expression. Artificial application of the mechanical strain induced expression of the GPC-4 gene that was related to the level of the strain. GPC-4 expression was strain dependent in other parts of the oviduct. In the ESG, GPC-4 was expressed exclusively by the glandular epithelium and not by the pseudostratified epithelium facing the lumen. In summary, we cloned the avian homologue of GPC-4, established its pattern of expression in the avian ESG, and demonstrated for the first time that this gene is regulated by mechanical strain.
authors.affiliation: Institute of Animal Science, Agricultural Research Organization, The Volcani Center, Bet Dagan 50250, Israel.
authors.forename: Irena
authors.initials: I
authors.lastname: Lavelin
authors.forename: Noam
authors.initials: N
authors.lastname: Meiri
authors.forename: Miriam
authors.initials: M
authors.lastname: Einat
authors.forename: Olga
authors.initials: O
authors.lastname: Genina
authors.forename: Mark
authors.initials: M
authors.lastname: Pines
mesh_terms: D000595:Amino Acid Sequence / Q000235:genetics; D000818:Animals; D001483:Base Sequence / Q000235:genetics; D002642:Chick Embryo / Q000502:physiology*; D004528:Egg Shell / Q000502:physiology*; D005260:Female; D019812:Heparan Sulfate Proteoglycans / Q000235:genetics*; D008969:Molecular Sequence Data; D010057:Oviducts / Q000502:physiology*; D013314:Stress, Mechanical
chemical_list: D019812:Heparan Sulfate Proteoglycans