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Molecular characterization and expression analysis of toll-like receptor 1 from large yellow croaker (Pseudosciaena
Kunru Wang1, Yinnan Mu, Tanglong Qian
1Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography, State Oceanic Administration, Xiamen 361005, PR China.
Abstract:
Toll-like receptors (TLRs) are a family of innate immune receptors that recognize molecular patterns associated with microbial pathogens (PAMP) and induce antimicrobial immune responses. Here we report the molecular cloning and characterization of a TLR1 homologue from the large yellow croaker (LycTLR1). The complete cDNA of LycTLR1 is 3487 nucleotides long, encoding a protein of 802 amino acids. The deduced LycTLR1 has a typical TLR domain architecture including 4 leucine-rich repeats (LRRs) (residues 42-491), one C-terminal LRR domain (residues 527-583) at the extracellular region and a TIR domain (residues 646-791) in the cytoplasmic region. Homology comparison shows that LycTLR1 has 76.8%-47.6% amino acid identity to known fish TLR1. Genomic analysis revealed that LycTLR1 consisted of only one exon in the coding region, which is conserved among other TLR1 from different mammalian species and fish analyzed to date, except the zebrafish. The mRNA of LycTLR1 was constitutively expressed in spleen, head kidney, blood, liver, heart, gills, intestine, brains and muscle, with the highest levels in spleen and blood. Upon stimulation with LPS, the LycTLR1 expression obviously increased in the anterior kidney cells of large yellow croaker, suggesting a role for LycTLR1 in the immune response to LPS.
Insights
Researchers cloned and characterized Toll-like receptor 1 (TLR1) from large yellow croaker. This fish TLR1 is expressed in various tissues and its levels increase upon LPS stimulation, indicating a role in innate immunity.
Area of Science:
- Immunology
- Molecular Biology
- Genomics
Background:
- Toll-like receptors (TLRs) are crucial innate immune receptors recognizing pathogen-associated molecular patterns (PAMPs).
- TLRs initiate antimicrobial responses against microbial pathogens.
Purpose of the Study:
- To clone and characterize a Toll-like receptor 1 (TLR1) homologue from large yellow croaker (LycTLR1).
- To investigate the expression and potential immune role of LycTLR1 in fish.
Main Methods:
- Molecular cloning of LycTLR1 cDNA.
- Bioinformatic analysis of LycTLR1 protein structure and homology.
- Genomic analysis of LycTLR1 exon structure.
- Quantitative analysis of LycTLR1 mRNA expression in various tissues and after LPS stimulation.
Main Results:
- The LycTLR1 cDNA is 3487 nucleotides, encoding an 802-amino acid protein with typical TLR domain architecture.
- LycTLR1 shares significant amino acid identity with known fish TLR1 homologues.
- LycTLR1 mRNA is constitutively expressed in multiple tissues, with highest levels in spleen and blood.
- LPS stimulation significantly upregulated LycTLR1 expression in anterior kidney cells.
Conclusions:
- The cloned LycTLR1 possesses conserved structural features of TLRs.
- Constitutive and inducible expression patterns suggest LycTLR1 plays a role in the innate immune response of large yellow croaker, particularly against LPS.
