Expression of mRNAs for laminin 1, 2, 4, and 5 chains in 1-week postnatal mouse bone marrow (BM), adherent cells from mouse long-term bone marrow cultures (LTBMC), 3T3, and MC3T3-G2/PA6 (PA6M) cell lines. Northern hybridization of total RNA was performed with the labeled cDNA probes corresponding to laminin 1, 2, 4, and 5 mRNA. Hybridizations with cDNA fragments corresponding to laminin 2, 4, and 5 mRNAs were performed consecutively on the same membrane. The amount of mRNA loaded was analyzed by hybridizations of the membranes with a cDNA probe corresponding to G3PDH mRNA (G3PDH). 28S; localization of 28S rRNA on the membranes. The blots were exposed to radiograph films; exposure time for a cDNA fragment corresponding to laminin 1 mRNA was 17 days, to laminin 2 mRNA 19 days, to laminin 4 mRNA 21 days, and to laminin 5 mRNA 28 days.