Candidate Pet-1 binding sites were identified based on similarity to the PEA3 site (Martin et al., 1988). The consensus binding site is based on sequences listed below, which show strong Pet-1 binding by mobility shift assay. Comparisons indicate that, in addition to the invariant GGA core, other obligatory nucleosides are thymidine at position +6 and adenosine or guanosine at position +4. Position +1 is the first guanosine residue in the invariant core. 5HT1aR, Serotonin receptor 1a; TPH, tryptophan hydroxylase; 5HTT, serotonin transporter; AADC, aromatic l-amino acid decarboxylase. h, Human; m, mouse. Numbers in parentheses indicate position of a Pet-1 binding site in the 5′ flanking region of the indicated gene. R = G or A, M = A or C. The lowercase letters indicate exceptions to the consensus.