Cloning and analysis of the full-length cDNA sequences of the heat shock protein 70 gene from silver carp,grass carp and Nile tilapia
鲢鱼、草鱼和尼罗罗非鱼热休克蛋白70基因cDNA全序列的克隆与分析

Heat shock protein 70 (HSP70) full-length cDNAs were cloned from the liver of two phytoplanktivorous freshwater fish, silver carp (Hypophthalmichthys molitrix) and Nile tilapia (Oreochromis nilotica), and one herbivorous fish, grass carp (Ctenopharyngodon idella) using RT-PCR and RACE. Sequence analysis revealed that the silver carp, grass carp, and Nile tilapia HSP70 cDNAs were 2356, 2348, and 2242 bp in length, and contained an open-reading frame (ORF) of 1950 bp (encoding a polypeptide of 649 amino acids), 1950 bp (encoding a polypeptide of 649 amino acids), 1917 bp (encoding a polypeptide of 638 amino acids), respectively. Silver carp, grass carp and Nile tilapia HSP70 sequences are highly homologous to other fish, amphibia and mammals HSP70, which suggests that they play a role in fundamental cellular processes. Results of the phylogenetic analysis revealed that silver carp and grass carp HSP70 formed a cluster with other cyprinid fishes, such as zebrafish and silver prussian carp, but Nile tilapia HSP70 formed a distinct cluster. This is consistent with the result that the cloned silver carp and grass carp HSP70 may belong to heat shock cognate 70, whereas the cloned Nile tilapia HSP70 may be classified as inducible heat shock protein 70.