title: The extracellular matrix of hydra is a porous sheet and contains type IV collagen.
abstract: Hydra, as an early diploblastic metazoan, has a well-defined extracellular matrix (ECM) called mesoglea. It is organized in a tri-laminar pattern with one centrally located interstitial matrix that contains type I collagen and two sub-epithelial zones that resemble a basal lamina containing laminin and possibly type IV collagen. This study used monoclonal antibodies to the three hydra mesoglea components (type I, type IV collagens and laminin) and immunofluorescent staining to visualize hydra mesoglea structure and the relationship between these mesoglea components. In addition, hydra mesoglea was isolated free of cells and studied with immunofluorescence and scanning electron microscopy (SEM). Our results show that type IV collagen co-localizes with laminin in the basal lamina whereas type I collagen forms a grid pattern of fibers in the interstitial matrix. The isolated mesoglea can maintain its structural stability without epithelial cell attachment. Hydra mesoglea is porous with multiple trans-mesoglea pores ranging from 0.5 to 1 microm in diameter and about six pores per 100 microm(2) in density. We think these trans-mesoglea pores provide a structural base for epithelial cells on both sides to form multiple trans-mesoglea cell-cell contacts. Based on these findings, we propose a new model of hydra mesoglea structure.
authors.affiliation: National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Shimizu
authors.affiliation: Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA; Institute of Zoology and Center for Molecular Biosciences, University of Innsbruck, A-6020 Innsbruck, Austria.
authors.forename: Roland
authors.initials: R
authors.lastname: Aufschnaiter
authors.affiliation: Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA.
authors.forename: Li
authors.initials: L
authors.lastname: Li
authors.affiliation: Department of Cell Biology and Anatomy, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Sarras
authors.affiliation: Division of Nephrology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
authors.forename: Dorin-Bogdan
authors.initials: DB
authors.lastname: Borza
authors.affiliation: Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA.
authors.forename: Dale R
authors.initials: DR
authors.lastname: Abrahamson
authors.affiliation: Shigei Medical Research Institute, Yamada, Okayama 701-0202, Japan.
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Sado
authors.affiliation: Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA.
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Zhang
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D024141:Collagen Type IV / Q000648:ultrastructure*; D005109:Extracellular Matrix / Q000648:ultrastructure*; D005455:Fluorescent Antibody Technique / Q000662:veterinary; D006829:Hydra / Q000033:anatomy & histology* / Q000166:cytology* / Q000502:physiology / Q000648:ultrastructure; D007797:Laminin / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning / Q000379:methods / Q000662:veterinary; D008954:Models, Biological; D009024:Morphogenesis
chemical_list: D000911:Antibodies, Monoclonal; D024141:Collagen Type IV; D007797:Laminin