Cloning of flounder STAT1 cDNA. (A) Comparison of the domain structure of human STAT1 to zebrafish STAT1. ND, N-domain responsible for dimer-dimer interactions; COILED-COIL, coiled-coil domain responsible for protein-protein interactions; DNA, DNA-binding domain; SH2, src homology 2 domain responsible for receptor binding and dimerization. (B) The degenerative PCR primers used in the experiments. (C) PCR strategies used to clone flounder STAT1. The STAT5'-1 and STAT3' primers were used for first-round PCR, and the STAT5'-2 and STAT3' primers were used for nested PCR.