Figure 3.

(A) Diagram of the full-length cDNA encoding the deoxyuridine triphosphatase of C. elegans (GenBank accession no. U96695). The positions of 10 bp derived from the 22-bp spliced leader (SL1), the poly(A) tail (represented by AAA), and the start (ATG) and stop (TAA) codons are shown. The positions of five motifs characteristic of dUTPase genes (25), each present three times, are represented by solid boxes. (B) The nucleotide sequences encoding the amino acid motifs 3 and 5 in each of the homologous repeats of the dUTPase gene, beneath the amino acids that they encode. Third codon positions are shown in boldface type. Beneath these nucleotide sequences are shown the two series of oligonucleotides containing base analogues that were examined for their ability to prime at these positions.