Abstract Primordial germ cells are an embryonic cell line that give rise to gametes in vertebrates. They origi- nate outside the embryo proper and migrate by a well- defined route to the genital ridges. Proteoglycans and glycosaminoglycans have distinctive properties that af- fect many of the characteristics of the extracellular mi- croenvironment of migratory pathways in a variety of developmental systems. The purpose of this work was to identify the proteoglycans and glycosaminoglycans that are spatially and temporally expressed in the migratory pathway of primordial germ cells. We showed that the expression of proteoglycans and glycosaminoglycans in the primordial germ cells migratory pathway changes ac- cording to the different phases of the migratory process. Some molecules such as chondroitin-0-sulfate, decorin, and biglycan are present only in certain phases of the mi- gratory process of primordial germ cells. Heparan sul- fate, chondroitin-6-sulfate, versican, perlecan, and syn- decan-4, although exhibiting some variation in expres- sion were detected during all phases of the migratory process. Our results indicate that the successive steps of primordial germ cell migration require a coordinated ex- pression of proteoglycans and glycosaminoglycans, that should be present in appropriate levels and in specific areas of the embryo, and that the sequential expression of these extracellular matrix molecules is under a genetic program that appears to be common to a variety of cell types during embryonic development. Keywords Primordial germ cells · Glycosaminoglycans · Proteoglycans · Cell migration · Extracellular matrix Introduction Cell migration is a common event during embryonic de- velopment and is crucial for the formation of tissues and organs. The extracellular matrix (ECM), according to the circumstances, facilitates or inhibits the cell migration (Heasman et al. 1981; Turner et al. 1983; Erickson 1990; Hammarback et al. 1988; Erickson and Perris 1993). Primordial germ cells (PGCs) are an embryonic cell line that give rise to gametes in vertebrates. They origi- nate outside the embryo proper very early in develop- ment and migrate by a well-defined route to the genital ridges (Witschi 1948; Chiqouine 1954). The PGCs mi- gration has four distinct phases. During the first phase, PGCs are passively carried from the endoderm of the yolk sac into the hindgut endoderm, as a result of embry- onic folding. In the second phase, the separation phase, the PGCs leave the hindgut epithelium and enter the ECM of the dorsal mesentery. The third phase is the migration phase, when the PGCs migrate by amoeboid movements between the mesenchymal cells of the dorsal mesentery toward the genital ridges. Finally, in the colo- nization phase, PGCs arrive at and populate the genital ridges (Fujimoto et al. 1977). Current evidence suggests that ECM components may be responsible for defining the route and pattern of PGC migration. Adhesive proteins, such as fibronectin, were found in the PGC migratory route (Fujimoto et al. 1985; Alvarez-Buylla and Merchant-Larios 1986) and were found to adhere to the PGCs, stimulating their migration (Alvarez-Buylla and Merchant-Larios 1986; Ffrench- Constant et al. 1991). Laminin and type IV collagen, were also found in the PGC pathway as well as in the basal laminae that surrounds the PGC migratory route (Garcia-Castro et al. 1997; Soto et al. 1998). Moreover, the PGCs were shown to adhere to the E3 domain of laminin (Garcia-Castro et al. 1997). M. Soto-Suazo · S. San Martin · T.M.T. Zorn ( ✉ ) Laboratory of Biology of Reproduction, Department of Histology and Embryology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, 05508-900, Brazil e-mail: temtzorn@usp.br Tel.: +55-11-30917260, Fax: +55-11-30917309 M. Soto-Suazo University of Santiago de Chile, Chile E.S. Ferro Laboratory of Cell Communication, Department of Histology and Embryology, Institute of Biomedical Sciences, University of São Paulo, Brazil Histochem Cell Biol (2002) 118:69–78 DOI 10.1007/s00418-002-0414-2 ORIGINAL PAPER Mauricio Soto-Suazo · Sebastian San Martin Emer S. Ferro · Telma M.T. Zorn Differential expression of glycosaminoglycans and proteoglycans in the migratory pathway of the primordial germ cells of the mouse Received: 23 April 2002 / Published online: 26 June 2002 © Springer-Verlag 2002