Figure 3.
RLN3 and INSL3 evolved from a bifunctional ligand. (A) Schematic presentation of the expression constructs encoding Myc- and 6-histidine-tagged relaxin family peptides linked with a mini-C domain. Mature B and A chain sequences of AncRFLC are shown (bottom). Two inter-chain and one intra-chain disulfide bridges are indicated by red lines. (B–E) LGR7 (RXFP1)- and LGR8 (RXFP2)-activation activities of human RLN3 and INSL3 (B), a resurrected ancestral RFLC peptide (AncRFLC) (C), two zebrafish RFLC peptides (zRFLC1 and zRFLC2) (D), and two platypus RFLC paralogs (pRFLCI and pRFLCII) (E). Mean ± SEM, N = 4.
