Figure 4.

Region of the Arabidopsis genome spanning the BIO3-BIO1 junction. Exons are shown in capital letters (orange) and introns in lower case (blue). Boxed and underlined sequences identify potential start and stop codons for bicistronic and single gene transcripts. The long BIO1 start site is located upstream of the long BIO3 stop site. Alternative BIO3 stop and BIO1 start sites for translation are underlined. The large boxed (+10) region is differentially spliced from the full-length monocistronic transcript (GenBank accession no. EU089963). RT-PCR primers are noted beneath the sequence with black (BIO3, forward), green (BIO1, long), violet (BIO1, short), and red (BIO3, reverse) arrows. Flanking sequences from bio3-3 begin at green (Oklahoma State sequence) and red (Salk sequence) arrowheads located within the second exon.