Expression patterns of focal adhesion associated proteins in the developing retina.
Adhesive interactions between integrin receptors and the extracellular matrix (ECM) are intimately involved in regulating development of a variety of tissues within the organism. In the present study, we have investigated the relationships between beta(1) integrin receptors and focal adhesion associated proteins during eye development. We used specific antibodies to examine the distribution of beta(1) integrin ECM receptors and the cytoplasmic focal adhesion associated proteins, talin, vinculin, and paxillin in the developing Xenopus retina. Immunoblot analysis confirmed antibody specificity and indicated that beta(1) integrins, talin, vinculin, and paxillin were expressed in developing retina and in the retinal-derived Xenopus XR1 glial cell line. Triple-labeling immunocytochemistry revealed that talin, vinculin, paxillin, and phosphotyrosine proteins colocalized with beta(1) integrins at focal adhesions located at the termini of F-actin filaments in XR1 cells. In the retina, these focal adhesion proteins exhibited developmentally regulated expression patterns during eye morphogenesis. In the embryonic retina, immunoreactivities for focal adhesion proteins were expressed in neuroepithelial cells, and immunoreactivity was especially strong at the interface between the optic vesicle and overlying ectoderm. At later stages, these proteins were expressed throughout all retinal layers with higher levels of expression observed in the plexiform layers, optic fiber layer, and in the region of the inner and outer limiting membrane. Strong immunoreactivities for beta(1) integrin, paxillin, and phosphotyrosine were expressed in the radially oriented Müller glial cells at later stages of development. These results suggest that focal adhesion-associated proteins are involved in integrin-mediated adhesion and signaling and are likely to be essential in regulating retinal morphogenesis.
Li
Ming
M
Department of Zoology and Genetics, Iowa State University, Ames, Iowa 50011, USA.
Sakaguchi
Donald S
DS
D000818:Animals; D015153:Blotting, Western; D002448:Cell Adhesion; D002460:Cell Line; D003598:Cytoskeletal Proteins / Q000378:metabolism; D005109:Extracellular Matrix / Q000378:metabolism; D022001:Focal Adhesions; D015151:Immunoblotting; D007150:Immunohistochemistry; D019012:Integrin beta1 / Q000378:metabolism; D008856:Microscopy, Fluorescence; D009457:Neuroglia / Q000378:metabolism; D051419:Paxillin; D010750:Phosphoproteins / Q000378:metabolism; D019000:Phosphotyrosine / Q000378:metabolism; D012160:Retina / Q000196:embryology*; D014981:Xenopus / Q000196:embryology* / Q000378:metabolism; D029867:Xenopus Proteins
D003598:Cytoskeletal Proteins; D019012:Integrin beta1; C496060:PXN protein, Xenopus; D051419:Paxillin; D010750:Phosphoproteins; D029867:Xenopus Proteins; D019000:Phosphotyrosine