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Title: Influence of a reconstituted basement membrane and its components on casein gene expression and secretion in mouse mammary epithelial cells

Journal Article · · Proc. Natl. Acad. Sci. U.S.A.; (United States)

When primary mouse mammary epithelial cells are cultured on plastic, they rapidly lose their ability to synthesize and secrete most milk proteins even in the presence of lactogenic hormones, whereas cells cultured on release type I collagen gels show greatly enhanced mRNA levels and secretion rates of ..beta..-casein and of some other milk proteins. The authors show here that culture on a reconstituted basement membrane from Engelbreth-Holm-Swarm tumor (EHS) allows > 90% of cells to produce high levels of ..beta..-casein. By comparison, 30-40% of cells on released type 1 gels and only 2-10% of cells on plastic express ..beta..-casein after 6 days in culture. Because only 40% of cells from late pregnant gland produced ..beta..-casein before culture, the EHS matrix can both induce and maintain an increased level of casein gene expression. Individual basal lamina components were also evaluated. Type IV collagen and fibronectin had little effect on morphology and ..beta..-casein mRNA levels. In contrast, both laminin and heparan sulfate proteoglycan increased ..beta..-casein mRNA levels. Profound morphological differences were evident between cells cultured on plastic and on EHS matrix, the latter cells forming ducts, ductules, and lumina and resembling secretory alveoli. These results emphasize the vital role of the extracellular matrix in receiving and integrating structural and functional signals that can direct specific gene expression in differentiated tissues.

Research Organization:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
DOE Contract Number:
AC03-76SF00098
OSTI ID:
5653199
Journal Information:
Proc. Natl. Acad. Sci. U.S.A.; (United States), Vol. 84:1
Country of Publication:
United States
Language:
English