Smad nuclear interacting protein, SNIP1, mediates the ecdysteroid signal transduction in red crayfish Procambarus clarkii.

Abstract

A smad nuclear interacting protein 1 (SNIP1) homolog was identified in the crayfish Procambarus clarkii and this gene encoded a polypeptide of 288 amino acids. Phylogenic analysis showed that P. clarkii SNIP1 was highly homologous to that of invertebrates and shared a highly conserved FHA domain of SNIP proteins at the C-terminus. Quantitative real-time PCR (qRT-PCR) analysis showed that Pc-SNIP1 expression was higher in heart than that in other examined tissues. In addition, prokaryotic expression and purification of the recombinant SNIP1 protein were performed. SDS-PAGE and western blot analysis demonstrated that a 35 KDa recombinant protein was successfully expressed in Escherichia coli cells. The expression of Pc-SNIP1 was significantly up-regulated in hepatopancreas after 20-hydroxyecdysone induction. Knockdown of Pc-SNIP1 gene by small interfering RNA (siRNA) transfection had significant influence on the expression of some ecdysteroid-responsive genes in hepatopancreas, which were confirmed by qRT-PCR and western blot. All together, these results suggest that SNIP1 is involved in the physiological process regulated by ecdysteroid in P. clarkii.