Laminin Mediates Tissue-specific Gene Expression in Mammary Epithelia
Tissue-specific gene expression in mammary epithelium is dependent on the extracellular matrix as well as hormones. There is good evidence that the basement membrane provides signals for regulating beta-casein expression, and that integrins are involved in this process. Here, we demonstrate that in the presence of lactogenic hormones, laminin can direct expression of the beta-casein gene. Mouse mammary epithelial cells plated on gels of native laminin or laminin-entactin undergo functional differentiation. On tissue culture plastic, mammary cells respond to soluble basement membrane or purified laminin, but not other extracellular matrix components, by synthesizing beta-casein. In mammary cells transfected with chloramphenicol acetyl transferase reporter constructs, laminin activates transcription from the beta-casein promoter through a specific enhancer element. The inductive effect of laminin on casein expression was specifically blocked by the E3 fragment of the carboxy terminal region of the alpha 1 chain of laminin, by antisera raised against the E3 fragment, and by a peptide corresponding to a sequence within this region. Our results demonstrate that laminin can direct tissue-specific gene expression in epithelial cells through its globular domain.
- Research Organization:
- Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (US)
- Sponsoring Organization:
- Life Sciences Division
- DOE Contract Number:
- AC02-05CH11231
- OSTI ID:
- 1009841
- Report Number(s):
- LBNL-4367E
- Journal Information:
- Journal of Cell Biology, Journal Name: Journal of Cell Biology Journal Issue: 3 Vol. 129; ISSN 0021-9525
- Country of Publication:
- United States
- Language:
- English
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