Molecular cloning and expression of a Toll receptor in the giant tiger shrimp, Penaeus monodon

• Published in: Fish & Shellfish Immunology 2007-09, Vol.23 (3), p.504-513
• Main Authors: Arts, Joop A.J., Cornelissen, Ferry H.J., Cijsouw, Tony, Hermsen, Trudi, Savelkoul, Huub F.J., Stet, René J.M.
• Format: Article
• Language: English
• Subjects: activation; Amino Acid Sequence; Animals; Apis mellifera; bacteria; Base Sequence; Cloning, Molecular; crustaceans; DNA, Complementary - chemistry; drosophila toll; evolution; Gene Expression Regulation; immune-responses; Innate immunity; Marine; pathway; Penaeidae - genetics; Penaeidae - metabolism; Penaeidae - virology; Penaeus monodon; peptidoglycan recognition protein; Phylogeny; sequence; Sequence Alignment; Toll; Toll-Like Receptors - chemistry; Toll-Like Receptors - genetics; White spot syndrome virus; White spot syndrome virus 1 - physiology; WSSV
• ISSN: 1050-4648; 1095-9947; 1365-2567
• DOI: 10.1016/j.fsi.2006.08.018

Invertebrates rely completely for their protection against pathogens on the innate immune system. This non-self-recognition is activated by microbial cell wall components with unique conserved molecular patterns. Pathogen-associated molecular patterns (PAMPs) are recognised by pattern recognition receptors (PRRs). Toll and its mammalian homologs Toll-like receptors are cell-surface receptors acting as PRRs and involved in the signalling pathway implicated in their immune response. Here we describe a novel partial Toll receptor gene cloned from a gill library of the giant tiger shrimp, Penaeus monodon, using primers based on the highly conserved Toll/IL-1R (TIR) domain. The deduced amino acid sequence of the P. monodon Toll (PmToll) shows 59% similarity to a Toll-related protein of Apis mellifera. Analysis of the LRRs of shrimp Toll contained no obvious PAMP-binding insertions. Phylogenetic analysis with the insect Toll family shows clustering with Toll1 and Toll5 gene products, and it is less related to Toll3 and Toll4. Furthermore, RT-qPCR shows that PmToll is constitutively expressed in gut, gill and hepatopancreas. Challenge with white spot syndrome virus (WSSV) shows equal levels of expression in these organs. A role in the defence mechanism is discussed. In conclusion, shrimp possess at least one Toll receptor that might be involved in immune defence.