In cell cultures of quail, chick, or mouse skeletal muscle, both myogenic and fibrogenic cells
synthesize and secrete type-IV collagen, a major structural component of the basal lamina.
Type-IV collagen, together with laminin, forms characteristic patches and strands on the
surface of developing myotubes, marking the onset of basement-membrane formation. The
pattern for type-IV collagen and laminin is unique to these proteins and is not paralleled by
other matrix proteins, such as fibronectin or type-I or-III collagen. In the present study, we …