title: Identification and expression analysis of two Toll-like receptor genes from sea cucumber (Apostichopus japonicus).
abstract: Toll-like receptors (TLRs) are a family of type I integral membrane glycoproteins which play pivotal roles in innate immunity. In this study, two TLRs named AjTLR3 and AjToll were cloned from sea cucumber (Apostichopus japonicus). The full-length cDNA sequences of AjTLR3 and AjToll are 3484 bp and 4211 bp, with an open reading frame (ORF) of 2679 bp and 2853 bp, encoding 892 and 950 amino acids, respectively. Both AjTLR3 and AjToll are composed of a leucine-rich repeat (LRR) domain, a transmembrane (TM) domain and an intracellular Toll/interleukin-1 receptor (TIR) domain. Evolution analysis revealed that AjTLR3 and AjToll were clustered with the vertebrate-like TLRs (V-TLRs) and the protostome-like TLRs (P-TLRs), respectively. These two genes were widely expressed in all five tested tissues (body wall, coelomocytes, tube feet, intestine and respiratory tree), but showed different expression patterns. The significantly up-regulated expressions of AjTLR3 and AjToll after peptidoglycan (PGN), lipopolysaccharides (LPS), Zymosan A and polyinosinic-polycytidylic acid (PolyI:C) challenges suggested that they were functionally involved in the immune responses to the Cram-positive bacteria, Gram-negative bacteria, fungi and double-stranded RNA (dsRNA) viruses, respectively.
authors.affiliation: Liaoning Key Laboratory of Marine Fishery Molecular Biology, Liaoning Ocean and Fisheries Science Research Institute, Dalian, Liaoning 116023, PR China.
authors.forename: Hongjuan
authors.initials: H
authors.lastname: Sun
authors.forename: Zunchun
authors.initials: Z
authors.lastname: Zhou
authors.forename: Ying
authors.initials: Y
authors.lastname: Dong
authors.forename: Aifu
authors.initials: A
authors.lastname: Yang
authors.forename: Bei
authors.initials: B
authors.lastname: Jiang
authors.forename: Shan
authors.initials: S
authors.lastname: Gao
authors.forename: Zhong
authors.initials: Z
authors.lastname: Chen
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Guan
authors.forename: Bai
authors.initials: B
authors.lastname: Wang
authors.forename: Xiuli
authors.initials: X
authors.lastname: Wang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D005786:Gene Expression Regulation; D007113:Immunity, Innate; D008969:Molecular Sequence Data; D009928:Organ Specificity; D010802:Phylogeny; D011070:Poly I-C / Q000494:pharmacology; D011135:Polysaccharides, Bacterial / Q000494:pharmacology; D060888:Real-Time Polymerase Chain Reaction; D016415:Sequence Alignment; D047528:Stichopus / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D051193:Toll-Like Receptors / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D015054:Zymosan / Q000494:pharmacology
chemical_list: D018076:DNA, Complementary; D011135:Polysaccharides, Bacterial; D051193:Toll-Like Receptors; D015054:Zymosan; D011070:Poly I-C