Molecular cloning of a novel laminin chain, α5, and widespread expression in adult mouse tissues

We have identified a fifth member of the α subfamily of vertebrate laminin chains. Sequence analysis revealed a close relationship of α5 to the only known Drosophila α chain, suggesting that the ancestral α gene was more similar to α5 than to α1-4. Analysis of RNA expression showed that α5 is widely expressed in adult tissues, with highest levels in lung, heart, and kidney. Our results suggest that α5 may be a major laminin chain of adult basal laminae.