Figure 5.

Partial nucleotide sequence of the genomic DNA around intron 1. The numbers in this figure refer to the nucleotide positions of the cDNA of Fig. 2. Uppercase and lowercase letters represent the nucleotides in exons 1 and 2 and in intron 1, respectively. The three gt splicing donor sites and the two ag acceptor sites are underlined and printed in boldface type. The three donor and two acceptor sites give six possible mRNAs, of which four have been identified. The four identified mRNAs have the combinations d1/a1 (donor 1/acceptor 1), d1/a2, d2/a2, and d3/a2. Fig. 2 corresponds to d3/a2.