Structurally diverse genes encode Tlr2 in rainbow trout: The conserved receptor cannot be stimulated by classical ligands to activate NF-κB in vitro.

摘要: The mammalian toll-like receptor 2 (TLR2) is a dominant for the recognition of Gram-positive bacteria. Its structure and functional properties were unknown in salmonid fish. In RT-PCR RACE experiments, we obtained full-length cDNA sequence encoding Tlr2 from rainbow trout (Oncorhynchus mykiss) as well copy an unspliced nonsense message highly segmented gene. primary encoded complies with domain ligand-binding sites known mammals other fish species sorts into evolutionary tree teleostean Tlr2s. We retrieved gene version on single exon (tlr2a) also partial second variant being multiple exons (tlr2b). Surprisingly, abundances both transcript variants accounted only ∼10% all Tlr2-encoding transcripts various tissues cell types healthy This suggests expression several distinct tlr2 trout. expressed tlr2a HEK-293 cells, but unable to demonstrate its functionality through NF-κB activation. Neither synthetic lipopeptides stimulate TLR2 nor different bacterial challenges induced OmTLR2-mediated activation, not or salmon CHSE-214 cells. Positive demonstration TLR2-MYD88 interaction excluded that impairment caused failure discuss impaired heterodimerization necessary Tlr partner one among alternatives explain dysfunction Tlr2a interspecies reconstitution system TLR signaling.