Figure 1.

Lamprey Tp53 gene structure and isoforms. By performing 5′ RACE using different sets of primers, we were able to identify four isoforms of the lamprey Tp53 gene. We designated these isoforms as Lj-p53, Lj-Δ27p53, Lj-Δ30p53, and Lj-Δ108p53. Coding exons are designated by open boxes, and noncoding exons are indicated by the purple boxes. The transcription start site is indicated by an arrow, and the sizes of the 5′ introns are labeled. Lj-Tp53 exons that encode the Mdm2-interacting region and the DNA-binding domain are labeled. The novel N′-terminal segment of 11 amino acids that is fused in-frame to the main p53 sequence at amino acid 108 in Lj-Δ108p53 is underlined.