Molecular insights of the first gastropod TLR counterpart from disk abalone (Haliotis discus discus), revealing its transcriptional modulation under pathogenic?stress

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• 作者：Don Anushka S ; aruwan Elvitigala ; H.K.A. Premach ; ra ; Ilson Whang ; Bo-Hye Nam ; Jehee Lee
• 关键词：Novel TLR homolog ; Disk abalone ; Phylogenetic relationship ; Spatial expression of mRNA ; Transcriptional profiles under pathogenic stress
• 刊名：Fish & Shellfish Immunology
• 出版年：2013
• 出版时间：August, 2013
• 年：2013
• 卷：35
• 期：2
• 页码：334-342
• 全文大小：4081 K

文摘

Toll-like receptors (TLRs) are well-characterized pattern recognition receptors of innate immunity, known to induce immune responses against the pathogens by interacting with evolutionarily conserved pathogen-associated molecular patterns (PAMPs). In this study, a novel TLR homolog from disk abalone (Haliotis discus discus) was identified and characterized at molecular level. The open reading frame (ORF) of AbTLR is 3804?bp in length and encodes a 1268 amino acid peptide with a calculated molecular mass of 143.5?kDa. The deduced protein shows typical TLR domain architecture, with leucine rich repeats (LRR) and the toll-interleukin receptor (TIR) domain. Phylogenetic analysis revealed a close evolutionary relationship for AbTLR to its invertebrate counterparts, with close clustering to the molluscan homologs. Quantitative real-time PCR detected ubiquitous transcription of AbTLR in healthy tissues, but with highest levels in hemocytes. Differential transcriptional modulation of AbTLR was observed in abalone hemocytes and gills upon immune challenge, whereby Vibrio parahaemolyticus and purified lipopolysaccharide (LPS) enhanced the transcript level prominently. In addition, the viral hemorrhagic septicemia virus induced AbTLR transcription in hemocytes and gills, representing the first evidence of viral-induced immune response in mollusks to date. Collectively, our findings support a putative role for AbTLR in abalone antiviral and antibacterial defense.