Fig 1

(A) Despite different exon numbering i.e. 6a/6b in human and 7/8 in zebrafish orthologues, exon structure is entirely conserved. (B) jnk1a, jnk1b and JNK1 lie in syntenic chromosomal regions. (C) Cartoon showing how the 8 jnk1a/b transcripts result from alternate exon 7/8 usage and differing C-terminal extension. (D) Translation of zebrafish jnk1a and jnk1b transcripts showing amino acids from alternatively spliced exons. Black text indicates identical amino acids, green text indicates favourable amino acid substitutions and red text divergent amino acid residues. Both jnk1a and jnk1b genes are capable of producing Ex7 and short C-terminus containing transcripts that fully match human JNK1 transcripts. However, whilst Ex8 derived from jnk1b matches the human peptide, the Ex8 from jnk1a is divergent and contains a serine rather than threonine residue (*). In contrast whilst the long C-terminal extension provided by jnk1a matches the human, the jnk1b long terminal extension is highly divergent and differs by 9/39 amino acids including insertion of an additional threonine residue. See S1 Fig for full peptide sequences.