A cytokine receptor domeless restrains mud crab reovirus infection via JAK-STAT signaling pathway in mud crab (Scylla paramamosain).

JAK/STAT signaling pathways are associated with the innate immune system and play important roles in mediating immune responses to virus infection. Domeless is a unique receptor involved in invertebrate JAK/STAT pathway. In this study, a Domeless gene from Scylla paramamosain, named SpDOME, was cloned and characterized. The full length of SpDOME mRNA contains a 475 bp 5'untranslated region (UTR), an open reading frame (ORF) of 4188 bp and a 3'UTR of 195 bp. The SpDOME protein contains twenty-four amino acid signal peptide and six characteristic Domeless domains. In addition, the SpDOME showed 13 %-26 % identity and 44 %-60 % similarity to other DOME protein domains, respectively. The mRNA of SpDOME was expressed in all tissues, with higher expression in brain, intestine and ganglion, and lowest expression in hepatopancreas. Moreover, expression of SpDOME was significantly responsive to challenges by mud crab reovirus (MCRV), Poly(I:C) and LPS. Subcellular localization revealed that SpDOME were localized in the cytoplasm. SpDOME could activate SpSTAT to translocate from the cytoplasm to the nucleus, and significantly increase the transcription activity of the wsv069 promoter under stimulus of Poly(I:C) and LPS. Additionally, silencing of SpDOME in vivo increased the mortality of MCRV infected mud crab and the viral load in tissues and down-regulated the expression of multiple components of apoptosis and JAK-STAT pathways and almost all the examined immune effector genes. These findings suggest that SpDOME activates the JAK/STAT pathway and plays an important role in antiviral immunity in mud crab.