| In the present study, RACE was performed to clone the silver carp PEPCK cDNA and the sequence was analyzed. Under the previous work of construction of the silver carp, liver cDNA suppression subtractive hybridization libraries exposed to MC-LR. Then, semi-quantitative RT-RCR was used to analyze the transcriptional expression of the silver carp liver PEPCK after 1, 5, 10 h exposed to MC-LR. The results showed that silver carp possessed 2 605 base pair (bp) nucleotide that comprisesd of a 5'-UTR (un-translated region) of 101 bp, a 3'-UTR of 564 bp and a 1 911 bp open reading frame (ORF) which encoded 636 amino acids. Sequence analysis showed that the nucleotides and amino acids sequence identity of silver carp PEPCK were highest (97% and 99% respectively) with Erythroculter ilishaeformis, secondly with Danio rerio (more than 90%), and lowest with Platichthys stellatus (77% and 84% respectively), implying that PEPCK was highly conserved during the long course of evolution. Silver carp PEPCK has combined with oxalyl ethyl specific domain, as well as three chain phosphate of GTP-binding kinase 1 and kinase 2 motifs. On the other hand, significant increases in PEPCK transcriptional expression were observed in the livers of silver carp at 1, 5, 10 h after exposed to MCLR, this indicated PEPCK transcription was induced by exposing MC-LR at 1 h. These results were related to microcystin effects, and might be related with microcystin detoxification process. |
