Laminin α1 chain mediated reduction of laminin α2 chain deficient muscular dystrophy involves integrin α7β1 and dystroglycan

Transgenically introduced laminin (LN) all chain prevents muscular dystrophy in LN alpha 2 chain deficient mice. We now report increased integrin alpha 7B beta 1D synthesis in dystrophic LN alpha 2 chain deficient muscle. Yet, immunofluorescence demonstrated a reduced expression of integrin alpha 7B subunit at the sarcolemma. Transgenic expression of LN alpha 1 chain reconstituted integrin a7B at the sarcolemma. Expression of alpha- and beta-dystroglycan is enhanced in LN alpha 2 chain deficient muscle and normalized by transgenic expression of LN alpha 1 chain. We suggest that LN alpha 1 chain in part ameliorates the development of LN alpha 2 chain deficient muscular dystrophy by retaining the binding sites for integrin alpha 7B beta 1D and alpha-dystroglycan, respectively. (c) 2006 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.