The c-Jun N-terminal kinases(JNKs)are the members of the mitogen-activated protein kinase(MAPK)family and play important roles in mediating the environmental stress responses.Previous studies have shown that JNKs regulate development of vertebrates,especially axis development.Our recent studies have also shown that JNK1 is implicated in control of sex reversal of the ricefield eel.To further explore the functions of JNKs in control of development,we have cloned jnk3 from goldfish,and compared the tissue-specific and temporal expression patterns in both goldfish and zebrafish.Our results show that the full length of jnk3 cDNA from gold fish contains an open reading frame(ORF)of 1 293 bp coding for a deduced protein of 414 amino acids.The goldfish jnk3 cDNA is 94.1% identical with that from zebrafish,and 80.7% with that from human.The amino acid sequences are 99.7% identical between goldfish and zebrafish,and 93.4% between goldfish and human.jnk3 is highly expressed in the brain and to a much less degree,in the testis of adult goldfish.In zebrafish,jnk3 is also expressed in the two tissues with similar pattern.In addition,jnk3 is expressed at moderate level in the heart of zebrafish.During development of goldfish and zebrafish,jnk3 mRNA is initially detectable at the neurula stage,then has gradually increased from neurula to heart-beating stage,and maintains at high level from heartbeating to hatching larvae.Together,these results suggest that jnk3 may be important for the later development of fish embryos and also functions in adult tissues including brain,heart and testis.