CqToll participates in antiviral response against white spot syndrome virus via induction of anti-lipopolysaccharide factor in red claw crayfish Cherax quadricarinatus

• Published in: Developmental and comparative immunology Vol. 74; pp. 217 - 226
• Main Authors: Li, Yan-yao, Chen, Xiao-xiao, Lin, Feng-yu, Chen, Qiu-fan, Ma, Xing-yuan, Liu, Hai-peng
• Format: Journal Article
• Language: English
• Published: United States Elsevier Ltd 01.09.2017; Elsevier Science Ltd
• Subjects: Amino acids; Animals; Anti-lipopolysacchride factor; Antimicrobial Cationic Peptides - genetics; Antimicrobial Cationic Peptides - metabolism; Arthropod Proteins - genetics; Arthropod Proteins - metabolism; Astacoidea - immunology; Cells, Cultured; Cherax quadricarinatus; Cloning, Molecular; Crayfish; Crustaceans; Gene silencing; Hemocytes - physiology; Immune response; Immune system; Immunity, Innate; Leucine; Lipopolysaccharides; Pattern recognition; Pattern recognition receptors; Protein structure; Proteins; Receptors; RNA, Small Interfering - genetics; Tissue analysis; Toll receptor; Toll-like receptors; Toll-Like Receptors - metabolism; Toxins; Transcription; Transcription Factors, General - genetics; Transcription Factors, General - metabolism; Transcriptome; Viral envelope proteins; Viral Envelope Proteins - genetics; Viral Envelope Proteins - metabolism; Virus Diseases - immunology; Viruses; White spot syndrome; White spot syndrome virus; White spot syndrome virus 1 - immunology; Anti-lipopolysacchride factor; Toll receptor; Cherax quadricarinatus; White spot syndrome virus
• ISSN: 0145-305X; 1879-0089
• DOI: 10.1016/j.dci.2017.04.020

It is well known that Tolls/Toll like receptors (TLRs), a family of pattern recognition receptors, play important roles in immune responses. Previously, we found that a Toll transcript was increased in a transcriptome library of haematopoietic tissue (Hpt) cells from the red claw crayfish Cherax quadricarinatus post white spot syndrome virus infection. In the present study, a full-length cDNA sequence of Toll receptor (named as CqToll) was identified with 3482 bp which contained an open reading frame of 3021 bp encoding 1006 amino acids. The predicted structure of CqToll protein was composed of three domains, including an extracellular domain of 19 leucine-rich repeats residues, a transmembrane domain and an intracellular domain of 138 amino acids. Tissue distribution analysis revealed that CqToll was expressed widely in various tissues determined from red claw crayfish with highest expression in haemocyte but lowest expression in eyestalk. Importantly, significant lower expression of the anti-lipopolysacchride factor (CqALF), an antiviral antimicrobial peptide (AMP) in crustaceans, but not CqCrustin was observed after gene silencing of CqToll in crayfish Hpt cell cultures, indicating that the CqALF was likely to be positively regulated via Toll pathway in red claw crayfish. Furthermore, the transcription of both an immediate early gene and a late envelope protein gene VP28 of WSSV were clearly enhanced in Hpt cells if silenced with CqToll, suggesting that the increase of WSSV replication was likely to be caused by the lower expression of the CqALF resulted from the loss-of-function of CqToll. Taken together, these data implied that CqToll might play a key role in anti-WSSV response via induction of CqALF in a crustacean C. quadricarinatus. •CqToll was expressed widely in various tissues with highest expression in haemocyte but lowest expression in eyestalk.•CqToll positively regulated CqALF expression but not CqCrustin in crayfish Hpt cells.•CqToll might play a key role in anti-WSSV response via induction of CqALF in claw crayfish.