THE HUMAN ALPHA-3B IS A FULL-SIZED LAMININ CHAIN VARIANT WITH A WIDESPREAD TISSUE EXPRESSION THAN THE TRUNCATED ALPHA-3A

We report the molecular cloning of the human laminin alpha 3b chain va riant and its mRNA expression pattern in adult human tissues when comp ared to the alpha 3a variant. The mRNA encoding for the alpha 3b varia nt is about 11 kb and the predicted translation product carries the co mplete set of domains typical for a 'full-sized' laminin alpha chain. Apart from the similar domain structure of alpha 3b also the sequence of alpha 3 resulted more closely related to the alpha 5 than to the al pha 4 chain. Quantitative analysis of the RNA expression in a broad pa nel of adult human tissues indicated that the alpha 3b variant is more widely distributed than the alpha 3b shorter variant. (C) 1997 Federa tion of European Biochemical Societies.