Analysis of PEVE distribution and expression in planarian body (A) Six fragments of the planarian body presented in the scheme were used to prepare first-strand cDNA and genomic DNA samples, which were subsequently employed for PCR with oligonucleotide primers for PEVE ORFs. Lines 1–6 correspond to the tissue samples taken as shown at scheme. PCR was performed with oligonucleotide primers for ORF2S (5'-caacgatagtcaccggaatgtca-3' and 5'-gcggctcctgtcttgagtcc-3') and ORF4L: (5'-ttttcatcagcatgtccgttcg-3' and 5'-cctcggttcaggcatctgtttc-3') Each PCR cycle included 95°C for 10 s, 64°C for 15 s and 72°C for 40 s. twenty one cycles were performed in the case of genomic DNA samples and twenty four cycles in the case of cDNA samples. Line 7 – negative control. RNA sample from zone 4 was used for RT-PCR without prior first-strand cDNA synthesis. (B) Northern blot analysis of the ORF2S (line 2) and ORF1L (line 3) transcripts. Line 1 – negative control. Hybridization with ORF2S probe was performed on RNA sample pre-treated with RNase A. M – marker, 0,16–1.77 kb RNA ladder (Gibco BRL).