Figure 1.

Genomic organization of the human IL-16 gene. The seven exons are shown as black boxes and projected on the IL-16 mRNA. UT, untranslated 5′ and 3′ sequences; AAUAAA, poly(A) addition motifs. The fragments encoding the proline-rich region and the three PDZ domains of pro-IL-16 protein are indicated. The black bar below denotes the sequence coding for the mature IL-16 protein. The complete gene of approximately 12.8 kb was cloned and sequenced as six overlapping fragments depicted above the gene structure. The use of an alternative splice acceptor in intron 5, three nucleotides downstream of the regular site, generates a transcript with a missing alanine codon (not shown). This splice acceptor is predominantly used in mice because we were unable to find cDNAs encoding this alanine in murine PBMCs (19).