Fig A. Variation in S7 receptor transcripts during regeneration.

Changes in FPKM values for individual S7 transcripts (7.1–7.8) at early regenerative timepoints during tail regeneration from an excised D. japonica head fragment. Fig B. Sequence comparison with human GpCRs. Maximum likelihood cladogram (PhyML) of flatworm and mammalian GpCRs. Sequence homology suggests closest resemblance of D. japonica (S1, S4, S7; colored) and S. mansoni (grey) sequences to serotonergic GpCRs (dashed lines) compared to GpCRs with other ligand specificities (adrenergic, dopaminergic, histaminergic, muscarinic). Analysis was performed based on protein sequence alignment (MUSCLE). Human sequences were retrieved from Uniprot by the following identifiers: 5HTR1A, P08908; 5HTR1B, P28222; 5HTR1D, P28221; 5HTR1E, P28566; 5HTR1F, P30939; 5HTR2A, P28223; 5HTR2B, P41595; 5HTR2C, P28335; 5HTR4, Q13639; 5HTR5A, P47898; 5HTR6, P50406; 5HTR7, P34969; HRH1, P35367; HRH2, P25021; HRH3, Q9Y5N1; HRH4, Q9H3N8; ACM1, P11229; ACM2, P08172; ACM3, P20309; ACM4, P08173; ACM5, P08912; DRD1, P21728; DRD5, P21918; DRD2, P14416; DRD3, P35462; DRD4, P21917; ADRA1A, P35348; ADRA1B, P35368; ADRA1D, P25100; ADRB1, P08588; ADRB2, P07550. S. mansoni predicted transcripts [24] were retrieved from GeneDB by the identifiers Smp_149770, Smp_197700, Smp_126730, Smp_148210. Analysis was bootstrapped with 500 replicates. Table A. Diverse serotonergic antagonists cause bipolarity. Structurally diverse ligands evidenced to act as mammalian serotonergic blockers produce 2-headed worms in the planarian trunk fragment regeneration assay. Maximal penetrance of the two-headed phenotype is scored (highest level of bipolarity at doses of drugs that are not toxic). Compounds sources: 1Sigma Aldrich, 2Tocris Bioscience. Dataset A. Sequences used for RNAi for S7 receptors. Amino acid sequences for S7 receptors (derived from the transcriptome assembly). Regions used for RNAi (bold) were amplified by PCR from planarian cDNA and cloned into the RNAi vector (see Methods). Attempts at PCR amplification of S7.8 (lowest predicted expression by FPKM values) were unsuccessful. Dataset B. Sequences of S1 and S4 planarian 5-HT receptors. Amino acid sequences for 5-HT receptors (derived from the transcriptome assembly). (DOCX)