Proceedings of the National Academy of Sciences of the United States of America
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Proc. Natl. Acad. Sci. U.S.A. · Jun 1983
Topographical arrangement of basement membrane proteins in lactating rat mammary gland: comparison of the distribution of type IV collagen, laminin, fibronectin, and Thy-1 at the ultrastructural level.
The topographical distribution of type IV collagen, laminin, fibronectin, and the thymocyte differentiation antigen Thy-1 in the basement membrane of the lactating rat mammary gland was investigated. Small cubes of tissue, which had not been subjected to prior fixation or freezing, were incubated with monospecific or monoclonal antibodies to these proteins, and the antibodies were located by an indirect immunoperoxidase staining technique and observed in the electron microscope. The lamina densa stained uniformly with antibodies to type IV collagen and laminin. ⋯ These maxima occurred in regions adjacent to Thy-1-bearing stromal cells. Thus, the topographical distribution of proteins within a basement membrane varies in a nonrandom manner, and local factors can modify this distribution. We suggest that this topographical variability may play a role in cell recognition and signalling processes that occur across the basement membrane.