Antigenic drift as a mechanism for tumor evasion of destruction by cytolytic T lymphocytes
J. Clin. Invest. Xue-Feng Bai, et al. 111:1487 doi:10.1172/JCI17656 [Go to this article.]

Figure 2
Molecular lesions in the P1A gene of the recurrent tumors. (a) Chromatograms of sequencing reactions of both cDNA and genomic PCR products. Mutations in nucleotides are indicated by arrows, while the replaced AAs are colored red. (b) Restriction enzyme mapping of the subclones isolated either from the parental J558-Neo cells or from the recurrent tumor cell lines Tum 1 and Tum 2. AvaII recognizes GGT(A)CC, which can be generated in the mutant P1A(9L); Fnu4HI is specific for GCNGC, which is present in P1A(6R). The two enzymes failed to identify any mutation in 37 clones of J558-Neo tumor cells. However, they divided the Tum 1 clones into four groups and Tum 2 clones into two groups (shown in figure as G1, G2, G3, and G4). The proportion of clones within each group is presented underneath each photograph. All suggested mutations of Tum 2 and Tum 1 and lack of mutation in J558-Neo clones were confirmed by DNA sequencing. DNA sequencing also revealed that the uncut Tum 2 G2 subclones harbored two independent mutations, P1A(7P) and P1A(8G). (c) Expression of the P1A gene in the Tum 1 G2 clones. RNA was isolated and used for RT-PCR (lane 3 and lane 4). No product was observed when the reverse transcriptase (RT) was not used (lane 5). As a comparison, PCR products from genomic DNA were also produced (lane 1 and lane 2). Note that while the genomic DNA is apparently heterozygous at P9, only P1A(9L) RNA is observed in the tumor cells. WT, wild type.