FIG 1.

Discovery of novel ZAP isoforms. (A and B) Schematics of ZAPL and ZAPS (A) and the newly discovered ZAPXL and ZAPM (B). Light green shading indicates sequences shared by all four isoforms, whereas the hatched region is shared only between the XL and L isoforms. The XL and M isoforms of ZAP contain an extended exon 4 that is shaded dark green. The pink and blue lollipops represent nonsynonymous and synonymous single nucleotide polymorphisms found in the human ZAP gene in 293T cells, respectively. (C) Total RNA was isolated from 293T cells, cDNA was synthesized, and PCR was carried out with the indicated primers that target the shared extended exon 4 and the unique ZAPL/XL or ZAPS/M 3′ UTR. PCR was performed on duplicate 293T cDNA samples synthesized using oligo(dT)₂₀ or a ZAP-specific 3′-UTR primer, and the results were consistent.