Inhibition of laminin alpha 1-chain expression leads to alteration of basement membrane assembly and cell differentiation.
The expression of the constituent alpha 1 chain of laminin-1, a major component of basement membranes, is markedly regulated during development and differentiation. We have designed an antisense RNA strategy to analyze the direct involvement of the alpha 1 chain in laminin assembly, basement membrane formation, and cell differentiation. We report that the absence of alpha 1-chain expression, resulting from the stable transfection of the human colonic cancer Caco2 cells with an eukaryotic expression vector comprising a cDNA fragment of the alpha 1 chain inserted in an antisense orientation, led to (a) an incorrect secretion of the two other constituent chains of laminin-1, the beta 1/gamma 1 chains, (b) the lack of basement membrane assembly when Caco2-deficient cells were cultured on top of fibroblasts, assessed by the absence of collagen IV and nidogen deposition, and (c) changes in the structural polarity of cells accompanied by the inhibition of an apical digestive enzyme, sucrase-isomaltase. The results demonstrate that the alpha 1 chain is required for secretion of laminin-1 and for the assembly of basement membrane network. Furthermore, expression of the laminin alpha 1-chain gene may be a regulatory element in determining cell differentiation.
De Arcangelis
A
A
Institut National de la Santé et de la Recherche Médicale, Unité 381, Strasbourg, France.
Neuville
P
P
Boukamel
R
R
Lefebvre
O
O
Kedinger
M
M
Simon-Assmann
P
P
D001483:Base Sequence; D001485:Basement Membrane / Q000378:metabolism*; D018938:Caco-2 Cells; D002352:Carrier Proteins / Q000032:analysis; D002454:Cell Differentiation; D002455:Cell Division; D016764:Cell Polarity; D018920:Coculture Techniques; D003106:Colon / Q000166:cytology* / Q000378:metabolism; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / Q000032:analysis; D004847:Epithelial Cells; D005347:Fibroblasts; D015870:Gene Expression; D006801:Humans; D007797:Laminin / Q000032:analysis / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D008840:Microfilament Proteins / Q000032:analysis; D008871:Microvilli; D008969:Molecular Sequence Data; D016372:RNA, Antisense / Q000032:analysis / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis; D013393:Sucrase / Q000032:analysis; D014162:Transfection
D002352:Carrier Proteins; D007797:Laminin; D008840:Microfilament Proteins; D016372:RNA, Antisense; D012333:RNA, Messenger; C026615:villin; D013393:Sucrase; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases