Identification of 5′ ends by RACE and quantitation of novel LMP2-TR transcripts in NK- and T-cell tumor lines. (A) The schematic represents the exon structure of the LMP2 gene spanning the EBV TR. Numbers indicate the exact 5′ ends of 4 of 7 cDNAs identified by RACE (EBV genome coordinates: NC007605). Three other 5′ cDNA ends identified in SNK 6 (coordinates 19, 80, and 83) correspond to the intervening intron and beginning of exon 2; having not reached the TR region. (B) Quantitative RT-PCR results: Ct₀ represents the assay threshold of detection. LMP2 transcript Ct values are normalized to cellular GAPDH Ct values. The left y-axis represents Δ(Ct₀-Ct), while the right-hand y-axis shows the equivalent fold difference in transcript levels.