title: Assembly and alignment of fibronectin-coated gold beads into fibrils by human skin fibroblasts.
abstract: The assembly of fibronectin into fibrils was monitored by high voltage electron microscopy using 18 nm colloidal gold beads bound to fibronectin (Au18-fibronectin) or an amino terminal 70 kd fragment of fibronectin (Au18-70 kd) that blocks the incorporation of fibronectin into disulfide bonded fibrils. Subconfluent cultures of human skin fibroblasts were incubated with the colloidal gold complexes for 0.25, 0.5, 1.5 and 5 h. In fibroblast cultures incubated with Au18-fibronectin and Au18-70 kd fragments for 0.25 and 0.5 h, the complexes of Au18-fibronectin and Au18-70 kd fragment were observed bound to the cell surface in clusters near bundles of intracellular microfilaments, usually along the lateral edges of the fibroblasts. Fibroblast cultures incubated with Au18-fibronectin and Au18-70 kd fragment for 1.5 and 5 h showed a more linear arrangement of the Au18-fibronectin and Au18-70 kd fragment along the lateral and retracting edges and on filopodia. This alignment of Au18-fibronectin into linear arrangements on the fibroblast cell surface suggests that the assembly of fibronectin fibrils occurs on specific regions of the fibroblast.
mesh_terms: D008841:Actin Cytoskeleton / Q000648:ultrastructure*; D002478:Cells, Cultured; D003599:Cytoskeleton / Q000648:ultrastructure*; D004622:Embryo, Mammalian; D005347:Fibroblasts / Q000648:ultrastructure; D005353:Fibronectins / Q000378:metabolism*; D006046:Gold; D006801:Humans; D007231:Infant, Newborn; D008854:Microscopy, Electron; D012867:Skin / Q000378:metabolism / Q000648:ultrastructure*
chemical_list: D005353:Fibronectins; D006046:Gold