Molecular Cloning and Expression Determination of p38 MAPK from the Liver and Kidney of Silver Carp

The sequence of p38MAPK in silver carp (Hm-p38a) was cloned and sequenced. Additionally, the acute toxicity of crude microcystins (MCs) on silver carp and induction expression of Hm-p38a by MCs exposure were also determined in this study. The results reveal that the length of Hm-p38a is 2418 bp and it contains a 1086 bp open reading frame. Hm-p38a could encode 361 amino acids. Sequence analysis indicates that Hm-p38a contains the conserved structures of Thr-Gly-Tyr motif and substrate binding site Ala-Thr-Arg-Trp, and it is highly conserved in fish. Phylogenetic analysis reveals that Hm-p38a is more closely related to fish than mammals and it belongs to p38α subfamily. Moreover, Hm-p38a in silver carp is constitutively expressed in all examined tissues. In addition, our results indicate that MCs exposure significantly promotes the transcription of Hm-p38a in fish liver or kidney, suggesting that mitogen-activated protein kinase should also be the signal pathway of MCs hepatotoxicity in fish.