Characterization and comprehensive analysis of the miiuy croaker TLR2 reveals a direct evidence for intron insert and loss
- Authors
- Xu, T., Meng, F., Zhu, Z., and Wang, R.
- ID
- ZDB-PUB-121019-34
- Date
- 2013
- Source
- Fish & shellfish immunology 34(1): 119-128 (Journal)
- Registered Authors
- Keywords
- Miiuy croaker, genomic structure, gene expression, intron insertion, TLR2, evolution
- MeSH Terms
-
- RNA/metabolism
- Real-Time Polymerase Chain Reaction
- Amino Acid Sequence
- Animals
- Base Sequence
- Molecular Sequence Data
- Evolution, Molecular
- Phylogeny
- Cloning, Molecular
- Organ Specificity
- Sequence Alignment
- Toll-Like Receptor 2/chemistry
- Toll-Like Receptor 2/genetics*
- Toll-Like Receptor 2/metabolism
- Fish Proteins/chemistry
- Fish Proteins/genetics*
- Fish Proteins/metabolism
- Selection, Genetic*
- Injections, Intraperitoneal
- Perciformes/genetics*
- Vibrio/immunology
- Introns
- DNA, Complementary/metabolism
- PubMed
- 23069786 Full text @ Fish Shellfish Immunol.
Toll-like receptor 2 (TLR2) is a member of an ancient pattern recognition receptor family, conserved from insects to mammals and it is best known as a receptor for recognizing conserved components of Gram-positive bacteria. In present study, the genomic structure of TLR2 gene from miiuy croaker was identified and characterized. It comprises twelve exons and eleven introns. The lengths of exons 3 to 10 of miiuy croaker TLR2 and exons 2 to 9 of fugu and pufferfish TLR2 are exactly the same, but most importantly, both of fugu and pufferfish have only eleven exons and ten introns. An intron insert event probably happened on exon 1 of miiuy croaker TLR2 after its divergence from ancestor of zebrafish, and an intron loss event probably happened on those of Tetraodontiformes TLR2 after the divergence with ancestor of miiuy croaker. Our study shows the direct evidence and strongly supports the intron insert and loss on fish TLR2. The pathogen injection experiments indicated that TLR2 may not be an important responder to Gram-negative bacteria in miiuy croaker. Molecular evolutionary analyses indicate TLR2 genes are under strong purifying selection pressure, showing a quite strong functional constraint in both of fish and mammals, despite of their distinct living environment conditions.