Secretion of chondroitin sulfate from embryonic epidermal cells in Xenopus laevis.
We examined proteoglycans (PGs) in amphibian epidermal cells by immunofluorescence microscopy. Immunoelectron microscopy with pre- and post-embedding methods, combined with HRP- or gold-conjugated secondary antibody, revealed ultrastructural localization of glycosaminoglycans (GAGs). Embryonic epidermis secretion granules in Xenopus laevis contained chondroitin 6-sulfate and unsulfated chondroitin. Immature secretion granules were also labeled with anti-chondroitin 6-sulfate and anti-chondroitin. A step-wise digestion experiment on chondroitinase ABC revealed that fine filaments in the secretion granules were chondroitin sulfate chains. Inhibition experiments with brefeldin A revealed that the life of a secretion granule was 5-10 hr, suggesting that GAG secretion from embryonic epidermis is routed through a regulated pathway.
Nishikawa
S
S
Department of Biology, Tsurumi University, School of Dental Medicine, Yokohama, Japan.
Sasaki
F
F
D000818:Animals; D000935:Antifungal Agents / Q000494:pharmacology; D020126:Brefeldin A; D002807:Chondroitin / Q000032:analysis; D002809:Chondroitin Sulfates / Q000032:analysis / Q000378:metabolism*; D003517:Cyclopentanes / Q000494:pharmacology; D003594:Cytoplasmic Granules / Q000737:chemistry / Q000378:metabolism / Q000502:physiology; D000078404:Epidermal Cells; D004817:Epidermis / Q000196:embryology / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D006025:Glycosaminoglycans / Q000032:analysis; D016253:Microscopy, Immunoelectron; D013997:Time Factors; D014982:Xenopus laevis / Q000196:embryology*
D000935:Antifungal Agents; D003517:Cyclopentanes; D006025:Glycosaminoglycans; D020126:Brefeldin A; D002807:Chondroitin; D002809:Chondroitin Sulfates