cDNA cloning and expression pattern analysis of protein inhibitor of activated STAT (PIAS) of the mud crab, Scylla paramamosain

Protein inhibitor of activated STAT (PIAS) plays a critical role in the feedback modulation of various signaling pathways as a negative regulator. To further understand the role of PIAS in immune and stress response in mud crab (Scylla paramamosain), in the present study, a full-length cDNA of PIAS from S. paramamosain (SpPIAS) was cloned for the first time, which contained an open reading frame of 2364 bp encoding a polypeptide of 788 amino acids. Quantitative reverse transcription PCR (qRT-PCR) was used to analyze the tissue distribution of PIAS in mud crab. The results revealed that SpPIAS was expressed in hemocytes, heart, hepatopancreas, gills, stomach, intestines, muscle, connective tissue and gonad of S. paramamosain, and the higher expression levels were found in connective tissue and gonad. The expression levels of SpPIAS in hemocytes were up-regulated after challenge with Staphylococcus aureus, Vibrio harveyi, and white spot syndrome virus (WSSV) for 2-24 h, which suggested that SpPIAS was involved in the pathogen-resistant activities of mud crab. Furthermore, the RING-like domain (RLD) and Serine/Threonine rich repeat C-terminal domain (S/T) of SpPIAS were expressed by prokaryotic expression system and purified by glutathione Sepharose 4B chromatography. This study contributed to define the biological characteristics of SpPAIS and further demonstrate the critical role of SpPAIS in vivo during the pathogen infection.