GENOMIC ORGANIZATION OF THE HUMAN ALPHA-3 INTEGRIN SUBUNIT GENE

The alpha 3 beta 1 integrin is a receptor for various laminin isoforms and plays an important role in the maintenance of tissue integrity. W e have characterized the genomic structure of the complete gene for th e human alpha 3 integrin subunit. The gene contains 26 exons spanning a region of 36.3 kb of genomic DNA. Its structure closely resembles th at of alpha 6, another of the three integrin alpha-subunits that are p art of laminin receptors, except that it lacks the corresponding exon 5A, which encodes an X1 region in the extracellular domain of alpha 6. However, the alpha 3 gene contains the equivalent of an exon 5B for a n X2-like region, which in alpha 6 and alpha 7 is present only in cert ain tissue-specific alternative transcripts. The two A and B cytoplasm ic variants of alpha 3, which are common to the three laminin receptor integrin alpha-subunits, are encoded by separate exons. (C) 1998 Acad emic Press.