A novel LRR and Ig domain-containing protein could function as an immune effector in Crassostrea gigas. Issue 88 (May 2019)

• Record Type: Journal Article
• Authors: Wang, Xiudan; Zhao, Xiaoli; Yan, Chunyu; Jia, Zhihao; Lv, Zhao; Ma, Cuiping; Wang, Mengqiang
• Is Part Of: Fish & shellfish immunology. Issue 88(2019)
• Page Start: 318
• Page End: 327
• Publication Date: 2019-05
• Subjects: Crassostrea gigas -- Leucine-rich repeat domain -- Immunoglobulin domain -- LRRIG -- Pattern recognition receptor -- Immune effector; Fishes -- Immunology -- Periodicals; Shellfish -- Immunology -- Periodicals; Poissons -- Immunologie -- Périodiques; Crustacés -- Immunologie -- Périodiques; 571.9617
• DOI: 10.1016/j.fsi.2019.03.003
• Languages: English
• ISSNs: 1050-4648

Abstract

Abstract: A variety of combinations of leucine-rich repeat (LRR) and immunoglobulin-like (Ig) domains have been found and discovered in invertebrates and vertebrates, but the functions remain largely unexplored. In the present study, a novel LRR and Ig domain-containing protein (LRRIG), CgLRRIG-3, was identified and characterized from oyster Crassostrea gigas . It contained two typical LRR motifs, a LRRNT motif and an Ig domain and PSI-BALST and phylogeny analysis revealed that the sequence of CgLRRIG-3 was most related with leucine-rich repeat neuronal 1 proteins from vertebrate. Its mRNA transcripts were constitutively expressed in muscle, gill, hepatopancreas, mantle, gonad and hemocytes with the highest level in hepatopancreas. The mRNA expression level of CgLRRIG-3 in hemocytes could respond to the stimulations of variety PAMPs including lipopolysaccharide (LPS), peptidoglycan (PGN), glucan (GLU) and polyinosinic-polycytidylic acid (poly I:C). The recombinant proteins exhibited a wide PAMP binding repertoire to four typical PAMPs and could significantly induce the expression of CgTNF-1 and CgIL17-5 as well as increase phagocytosis in primary cultured oyster hemocytes. In hepatopancreas, CgLRRIG-3 was mainly distributed in the basolateral membrane of digestive tubule and the hemocoel sinusoid between the digestive tubules. And in hemocytes, the positive signal was mainly distributed in a special group of granulocytes. These results collectively indicated that CgLRRIG-3 could not only function as an immune effector. Highlights: ALRR and Ig domain containing protein was identified from Crassostrea gigas. It was expressed in all the tissues and highest expressed in hepatopancreas. It could bind PAMPs and respond to PAMPs. It could induce the expression of cytokines and phagocytosis in hemocytes. It specifically expressed in a sub-population of hemocytes.