Expression analysis of the Toll-like receptor and TIR domain adaptor families of zebrafish.
The zebrafish genomic sequence database was analysed for the presence of genes encoding members of the Toll-like receptors (TLR) and interleukin receptors (IL-R) and associated adaptor proteins containing a TIR domain. The resulting predictions show the presence of one or more counterparts for the human TLR1, TLR2, TLR3, TLR4, TLR5, TLR7, TLR8, TLR9, IL-1R and IL-18R genes and one copy of the adaptor genes MyD88, MAL, TRIF and SARM. In contrast to data for the pufferfish Fugu rubripes, zebrafish has two genes that are highly similar to human TLR4. In addition, one fish-specific TLR group can be distinguished that is closely related to the Drosophila melanogaster Toll-9 gene. The sequence of cloned cDNAs for TLR4, TLR2 and MyD88 show the same intron-exon organisation as in the human counterparts. Expression analysis using reverse transcriptase-PCR (RT-PCR) shows that 17 of the predicted zebrafish TLR genes and all the genes encoding adaptor proteins are expressed in the adult stage. A subset of the TLR genes are expressed at higher levels in fish infected with the pathogen Mycobacterium marinum. The induced genes include the homologues of the human TLR1 and TLR2 genes, whose functions are associated with mycobacterial infections, underscoring the suitability of zebrafish as a model for analysis of the vertebrate innate immune system.
Meijer
Annemarie H
AH
Institute of Biology, Leiden University, Wassenaarseweg 64, 2333 AL Leiden, The Netherlands. meijer@rulbim.leidenuniv.nl
Gabby Krens
S F
SF
Medina Rodriguez
Indira A
IA
He
Shuning
S
Bitter
Wilbert
W
Ewa Snaar-Jagalska
B
B
Spaink
Herman P
HP
D000818:Animals; D020869:Gene Expression Profiling; D053727:Interleukin-18 Receptor alpha Subunit; D008562:Membrane Glycoproteins / Q000096:biosynthesis / Q000235:genetics*; D005810:Multigene Family; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D011956:Receptors, Cell Surface / Q000096:biosynthesis / Q000235:genetics*; D018123:Receptors, Interleukin / Q000235:genetics; D017472:Receptors, Interleukin-1 / Q000235:genetics; D053724:Receptors, Interleukin-18; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D020539:Sequence Analysis, Protein; D017385:Sequence Homology; D051194:Toll-Like Receptor 1; D051195:Toll-Like Receptor 2; D051196:Toll-Like Receptor 3; D051197:Toll-Like Receptor 4; D051198:Toll-Like Receptor 5; D051199:Toll-Like Receptor 7; D051200:Toll-Like Receptor 8; D051193:Toll-Like Receptors; D015027:Zebrafish / Q000235:genetics* / Q000378:metabolism
C508572:IL18R1 protein, human; D053727:Interleukin-18 Receptor alpha Subunit; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; D018123:Receptors, Interleukin; D017472:Receptors, Interleukin-1; D053724:Receptors, Interleukin-18; D051194:Toll-Like Receptor 1; D051195:Toll-Like Receptor 2; D051196:Toll-Like Receptor 3; D051197:Toll-Like Receptor 4; D051198:Toll-Like Receptor 5; D051199:Toll-Like Receptor 7; D051200:Toll-Like Receptor 8; D051193:Toll-Like Receptors