Identification of the first toll-like receptor gene in passerine birds: TLR4 orthologue in zebra finch (Taeniopygia guttata).
Abstract
Toll-like receptors (TLRs) are the basic components of the vertebrate pathogen recognition system. Despite uniform general structure, remarkable variability in domain composition can be found in individual TLRs among species.
Knowledge of interspecific differences is of particular importance to our understanding of selective pressures on TLRs. Currently, most TLRs are characterized only in a limited number of model species, including domestic chicken as a universal avian model.
Here, we describe structure and expression pattern of TLR4 in zebra finch, a widely used passerine model species. The tgTlr4 gene consists of three exons (204, 167 and 3033–3043 bp) that are transcribed into messenger RNA.
Predicted protein is composed of 842 amino acids. The gene is highly expressed in the bone marrow and in the spleen.
For the first time in birds, expression of tgTLR4 in peritoneal macrophages was found to be enhanced by the Escherichia coli lipopolysaccharide treatment.