THE UNIQUE CYTOPLASMIC DOMAIN OF THE HUMAN INTEGRIN VARIANT BETA-4E IS PRODUCED BY PARTIAL RETENTION OF INTRONIC SEQUENCES

A novel cytoplasmic splice variant of the human beta 4 integrin subuni t has been identified by reverse transcription polymerase chain reacti on using mRNA from cultured keratinocytes as the template, This fifth beta 4 variant, called beta 4E, is expressed in a wide variety of tiss ues including the epidermis, lung duodenum, heart, spleen and stomach and in several human epithelial cell lines, The beta 4E cDNA contains an insert of 37 base pairs which produces a frame shift in the sequenc e encoding the beta 4 cytoplasmic domain and generates a new stop codo n after a stretch of cDNA encoding a unique 114-amino acid peptide. An alysis of the genomic organization at the site of this insertion in th e human beta 4 gene reveals that beta 4E is produced by partial retent ion of an intron in the final transcript. (C) 1997 Academic Press.