Figure 2.

Proposed stages of KIR gene activation during NK cell development. A schematic of the 5′ region of the KIR2DL1 gene is shown. Distal, intermediate, and switch promoters are indicated by rectangles labeled D, I, and S, respectively, and exons are shown as numbered rectangles. Active promoters in each stage are green, and inactive promoters are gray. Transcripts are shown by lines ending in arrows, and intronic regions are shown as dotted lines. The site of initiation of KIR protein translation is indicated by a vertical line labeled “ATG,” and the location of premature stop codons in alternative exons found in forward transcripts from Pro-S are indicated by “TGA.”