Primary Structure, Developmental Expression, and Immunolocalization of the Murine Laminin α4 Chain

Abstract

The complete primary structure of the mouse laminin ␣4 chain was derived from cDNA clones. The translation product contains a 24-residue signal peptide preceding the mature ␣4 chain of 1,792 residues. Northern analysis on whole mouse embryos revealed that the expression was weak at day 7, but it later increased and peaked at day 15. In adult tissues the strongest expression was observed in lung and cardiac and skeletal muscles. Weak expression was also seen in other adult tissues such as brain, spleen, liver, kidney, and testis. By in situ hybridization of fetal and newborn tissues, expression of the laminin ␣4 chain was mainly localized to mesenchymal cells. Strong expression was seen in the villi and submucosa of the developing intestine, the mesenchymal stroma surrounding the branching lung epithelia, and the external root sheath of vibrissae follicles, as well as in cardiac and skeletal muscle fibers. In the developing kidney, intense but transient expression was associated with the differentiation of epithelial kidney tubules from the nephrogenic mesenchyme. Immunohistologic staining with affinity-purified IgG localized the laminin ␣4 chain primarily to lung septa, heart, and skeletal muscle, capillaries, and perineurium.

Laminin α 3 Forms a Complex with β3 and γ3 Chains That Serves as the Ligand for α 6β1-Integrin at the Apical Ectoplasmic Specialization in Adult Rat Testes

“…Virtually all laminin chains were found in adult rat testes (Fig. 1), consistent with several earlier reports (33)(34)(35)(36). We next examined Sertoli and germ cells in the seminiferous epithelium that express different laminins.…”

Laminin isoform–specific promotion of adhesion and migration of human bone marrow progenitor cells

“…[32][33] Laminin ␣4 chain is synthesized by endothelial and mesenchymal cells and is also expressed at specific sites of loose connective tissue. 34 In the bone marrow, laminin ␣4 and ␣5 chains, assembled with ␤1 and ␥1 chains to form laminin-8 (␣4␤1␤1) and laminin-10 (␣5␤1␥1), are present in sinusoidal subendothelial basement membranes, and ␣4 laminins are in addition located in the intersinusoidal spaces. In contrast, laminin-1 has not been found in bone marrow in vivo, [35][36] in agreement with its expression mainly in a subset of epithelial basement membranes.…”

Identification of Biologically Active Sequences in the Laminin α4 Chain G Domain

“…The laminin ␣4 chain lacks the N-terminal short arm and is expressed in cells of mesenchymal origin, such as endothelial cells and adipocytes (23)(24)(25). Laminin ␣4 chain expression is mainly localized to mesenchymal cells present in the lung and cardiac and skeletal muscles fibers (26). The ␣4 chain is also weakly expressed in other adult tissues, such as brain, spleen, liver, kidney, and testis (26).…”

“…Laminin ␣4 chain expression is mainly localized to mesenchymal cells present in the lung and cardiac and skeletal muscles fibers (26). The ␣4 chain is also weakly expressed in other adult tissues, such as brain, spleen, liver, kidney, and testis (26). The laminin ␣4 chain may play a critical biological role in the tissues.…”