The nucleic acid binding protein PcCNBP is transcriptionally regulated during the immune response in red swamp crayfish Procambarus clarkii

Abstract

Cellular nucleic acid binding proteins (CNBPs) represent a highly conserved protein family among vertebrates; they harbour seven tandem zinc finger repeats CCHC type and have been described as transcriptional and translational regulators. To date, there is little characterization of CNBP in invertebrates since its structure and function have been analysed solely in Drosophila melanogaster. However, no CNBP has been investigated in other arthropod systems. In an effort to isolate immune-related genes in Procambarus clarkii, a partial mRNA coding a zinc finger containing protein was found to be up-regulated during the response to white spot syndrome virus (WSSV) infection. The red swamp crayfish P. clarkii represents an attractive animal model because of its tolerance to extreme environmental conditions and resistance to diseases. Thus it has become an important crustacean model organism for virological studies. In this study, a CNBP homolog from the red swamp crayfish Procambarus clarkii was characterised. The full length cDNA of PcCNBP was of 1257 bp with a 5’-untranslated region (UTR) of 63 bp and a 3’-UTR of 331 bp with a poly (A) tail and an open reading frame (ORF) of 864 bp, encoding a polypeptide of 287 amino acids with the predicted molecular weight of about 33 KDa. The predicted protein possesses 7 tandem repeats of 14 amino acids containing the CCHC zinc finger consensus sequence, two RGG-rich single stranded RNA-binding domain and a Nuclear localization signal, strongly suggesting that PcCNBP was a homolog of vertebrate CNBP. Analyses of transcriptional expression profile showed that PcCNBP was costitutively expressed among different tissues from the adult crayfish, under normal physiological conditions. Moreover, qRT-PCR assays indicate that the transcriptional expression of PcCNBP responds to bacterial and viral stimulation.