The transcriptomic expression of pattern recognition receptors: Insight into molecular recognition of various invading pathogens in Oyster Crassostrea gigas

• Published in: Developmental & Comparative Immunology
• Main Authors: Wang, Lingling, Zhang, Huan, Wang, Mengqiang, Zhou, Zhi, Wang, Weilin, Liu, Rui, Huang, Mengmeng, Yang, Chuanyan, Qiu, Limei, Song, Linsheng
• Format: Report
• Language: English
• Published: ELSEVIER SCI LTD 2019
• Subjects: Bivalve immunity; Pattern recognition receptors; Crassostrea gigas; Transcriptome; RNA-Seq; Fisheries; Immunology; Zoology; C-TYPE LECTINS; IMMUNE RECOGNITION; CONTAINING PROTEIN; GENOMIC ANALYSIS; GENE REPERTOIRE; REVEALS; SYSTEM; AGGLUTINATION; ADAPTATION; COMPLEXITY; Pacific; Pacific oyster
• Online Access: http://ir.qdio.ac.cn/handle/337002/156144; https://doi.org/10.1016/j.dci.2018.09.021

Pattern recognition receptors (PRRs) are essential in recognizing specific pathogen-associated molecular patterns (PAMPs) on microbes and triggering responses to eliminate the invading pathogens. Previous genomic studies have revealed a great number of PRR genes in the Pacific oyster Crassostrea gigas, a sessile and filter-feeder marine bivalve belonging to the phylum Mollusca. On the survey of PRRs in the assembly oyster reference genome version 9, a total of 1084 PRRs were identified, which were composed of at least 12 gene families. Some of the gene families were significantly expanded, including C-type lectins (CTLs), fibrinogen-related proteins (FREPs), scavenger receptor cysteine-rich repeat protein (SRCRs), leucine-rich repeat (LRR)-only proteins (LRRops), and especially Clq domain-containing proteins (ClqDCs). The transcriptomic profiles of these abundant PRRs in response to PAMP treatments were investigated by RNA-Seq using the SOLiD EZ BeadTM system. Compared to the control library, there were 6,655, 7,273, 7,593, 6,830, 6687 and 8250 differentially expressed genes in the haemocytes of oysters in response to lipopolysaccharide (LPS) stimulation for 6 h, 12 h and 24 h, and peptidoglycan (PGN), glucan (GLU) and poly I:C (IC) stimulation for 12 h, respectively. After stimulation for 12 h, there were 134, 97, 114 and 159 genes up-regulated in the LPS, PGN, GLU and IC library, respectively. Most of the gene families involved in immune response towards PAMPs were ClqDCs, CTLs and FREPs, while only a few members of LRR and immunoglobin-containing proteins (LRRIGs), retinoic acid-inducible gene I [RIG-I]-like receptors (RLRs) and Toll like receptors (TLRs) were up-regulated. After LPS stimulation, the expression level of 258 non-redundant PRR genes in oyster haemocytes increased significantly with different expression pattern, and most of them were ClqDCs, CTLs, LRRops and FREPs. The transcriptomic analyses indicated that there was a dynamic and orchestrated specific expression regulation of numerous PRR genes ...