Prediction of the prototype of the human Toll-like receptor gene family from the pufferfish, Fugu rubripes, genome

The insect Toll family of proteins and their mammalian counterparts seemingly shared one common ancestor and evolved independently. Here we demonstrated that the prototype of the mammalian-type (M-type) Toll family is shared by the fish and humans. According to the draft of the pufferfish Fugu genom...

Full description

Saved in:
Bibliographic Details
Published in:Immunogenetics (New York) 2003-02, Vol.54 (11), p.791-800
Main Authors: Oshiumi, Hiroyuki, Tsujita, Tadayuki, Shida, Kyoko, Matsumoto, Misako, Ikeo, Kazuho, Seya, Tsukasa
Format: Article
Language:English
Subjects:
Amino Acid Sequence
Animals
Base Sequence
DNA - genetics
Drosophila Proteins
Evolution, Molecular
Gene Expression
Humans
Membrane Glycoproteins - chemistry
Membrane Glycoproteins - genetics
Membrane Glycoproteins - immunology
Molecular Sequence Data
Multigene Family
Phylogeny
Protein Structure, Tertiary
Receptors, Cell Surface - chemistry
Receptors, Cell Surface - genetics
Receptors, Cell Surface - immunology
RNA, Messenger - genetics
Sequence Homology, Amino Acid
Species Specificity
Takifugu - genetics
Takifugu - immunology
Toll-Like Receptor 1
Toll-Like Receptor 4
Toll-Like Receptors
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The insect Toll family of proteins and their mammalian counterparts seemingly shared one common ancestor and evolved independently. Here we demonstrated that the prototype of the mammalian-type (M-type) Toll family is shared by the fish and humans. According to the draft of the pufferfish Fugu genome project, the signature Toll-IL-1 receptor homology domain (TIR domain) has been conserved during evolution. FuguTLR2, 3, 5, 7, 8 and 9 members correspond structurally to respective mammalian TLRs. One Fugu TLR showed equally high amino acid identity to human TLR1, 6 and 10, and we named it FuguTLR1. Fugu rubripes has genes for TLR21 and 22, which are unique to fish. One possible interpretation of these findings is that TLR1, 2, 3, 4, 5, 7, 8, 9, 21 and 22 existed in the ancestral genome common to fish and mammals, and that TLR4 was lost in the fish lineage, while TLR21 and 22 were lost in the mammalian lineage. Strikingly, a solitary ascidian, Halocynthia roretzi, has only a few Toll-like proteins, which, like Caenorhabditis elegans Toll, represent primitive ones before the expansion of the Toll family. Therefore, the expansion of TLR genes should have occurred earlier than fish, but not C. intestinalis, separated evolutionarily from mammals. These results infer that the appearance of the M-type innate system was completed before or concomitant with the appearance of acquired immunity. We interpret the present data to mean that the differences of TLRs identified in this study between fishes and humans may be rather peripheral, partially due to selection pressure exerted by pathogens in distinct environments.
ISSN:0093-7711
1432-1211
DOI:10.1007/s00251-002-0519-8