Physical map of the FcγRIIc-specific transcripts expressed in human NK cells. Sequence analysis of 16 cDNA clones obtained from four NK cell samples revealed the presence of four different alternatively spliced FcγRIIc-specific transcripts (IIc1-c4). IIc1 was identical with the already described FcγRIIc isoform; IIc2 transcript had a 14-bp insertion at the junction between the C2 and C3 exons; the IIc3 transcript had spliced out both the C1 and C2 exons; and IIc4 had an 85-bp insertion between the EC2 and TM exons and both the C1 and C2 exons spliced out.