A novel SNW/SKIP domain-containing protein, Bx42, is involved in the antibacterial responses of Macrobrachium nipponense. (December 2020)

• Record Type: Journal Article
• Authors: Xu, Liaoyi; Zhou, Xiefei; Wu, Yue; Yang, JingJing; Xu, Haisheng
• Is Part Of: Developmental and comparative immunology. Volume 113(2020)
• Publication Date: 2020-12
• Subjects: Bx42 -- SNW/SKIP domain-Containing peptide -- Macrobrachium nipponense -- Phagocytic activity -- Antibacterial immunity; Immunology -- Periodicals; Developmental immunology -- Periodicals; 616.079
• DOI: 10.1016/j.dci.2020.103788
• Languages: English
• ISSNs: 0145-305X

Abstract

Abstract: Bx42, the homologue of SNW1 in mammals, is involved in pre-mRNA splicing and transcriptional regulation. However, the presence and function of Bx42 have remained poorly understood in invertebrates until now. In the current study, a novel SNW domain-containing protein ( Mn Bx42) from Macrobrachium nipponense was identified, and its potential role in the immune response was investigated. The full-length Mn Bx42 was 7467 bp with an open reading frame of 1653 bp, encoding 550 amino acids. Real-time PCR analysis suggested that Mn Bx42 was predominantly expressed in the intestine, gills and hepatopancreas, and immunofluorescence assays indicated that it was located in the nucleus. Its expression level was significantly decreased in M. nipponense post-challenge with white spot syndrome virus (WSSV) as well as Aeromonas hydrophila and Staphylococcus aureus, implying its participation in the innate immune response. The knockdown of Mn Bx42 in vivo notably increased the susceptibility of the prawns to bacterial infection, markedly increased the bacterial load in the gills, and significantly attenuated the phagocytic activity of haemocytes. Dual-luciferase reporter assays illustrated that Mn Bx42 could activate the NF-κB pathway. Consistent with this, when Mn Bx42 was silenced in vivo, the expression levels of antimicrobial peptides (AMPs), including ALF2, ALF3, ALF4, ALF5, Cru1 and Cru2, and NF-κB signalling genes, including dorsal, relish, TAK1, TAB1, Ikkβ, and Ikkε, were significantly reduced. Taken together, these findings may provide new insights about Bx42 in crustaceans and pave the way for a better understanding of the crustacean innate immune system. Highlights: A novel SNW/SKIP domain-containing protein Bx42 was identified from Macrobrachium nipponense. Mn Bx42 gene expression was high in gills, intestine and hepatopancreas. Knockdown of Mn Bx42 increased the susceptibility of prawns to bacterial infection. Knockdown of MnBx42 reduced the expression of NF-κB signalling-related and antimicrobial peptide genes. Overexpression of Mn Bx42 in vitro significantly activated the promoter of NF-κB.