tokens: The RI alpha gene is composed of nine coding exons of varying lengths , separated by introns , giving the gene a total length of at least 21 kb . our recent cloning of a processed RI alpha pseudogene with a 5 ' - noncoding region different from the previously reported RI alpha complementary RNA indicated that the RI alpha gene may have multiple leader exons giving rise to alternately spliced messenger RNAs ( mRNAs ) .