Premium
The Pekin duck programmed death‐ligand 1: cDNA cloning, genomic structure, molecular characterization and mRNA expression analysis
Author(s) -
Yao Q.,
Fischer K. P.,
Tyrrell D. L.,
Gutfreund K. S.
Publication year - 2015
Publication title -
international journal of immunogenetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.41
H-Index - 47
eISSN - 1744-313X
pISSN - 1744-3121
DOI - 10.1111/iji.12175
Subject(s) - complementary dna , biology , coding region , microbiology and biotechnology , peptide sequence , exon , conserved sequence , messenger rna , amino acid , gene , genetics
Summary Programmed death ligand‐1 ( PD ‐L1) plays an important role in the attenuation of adaptive immune responses in higher vertebrates. Here, we describe the identification of the Pekin duck PD ‐L1 orthologue (du PD ‐L1) and its gene structure. The du PD ‐L1 cDNA encodes a 311‐amino acid protein that has an amino acid identity of 78% and 42% with chicken and human PD ‐L1, respectively. Mapping of the du PD ‐L1 cDNA with duck genomic sequences revealed an exonic structure of its coding sequence similar to those of other vertebrates but lacked a noncoding exon 1. Homology modelling of the du PD ‐L1 extracellular domain was compatible with the tandem IgV‐like and IgC‐like Ig SF domain structure of human PD ‐L1 ( PDB ID : 3 BIS ). Residues known to be important for receptor binding of human PD ‐L1 were mostly conserved in du PD ‐L1 within the N ‐terminus and the G sheet, and partially conserved within the F sheet but not within sheets C and C'. Du PD ‐L1 mRNA was constitutively expressed in all tissues examined with highest expression levels in lung and spleen and very low levels of expression in muscle, kidney and brain. Mitogen stimulation of duck peripheral blood mononuclear cells transiently increased du PD ‐L1 mRNA expression. Our observations demonstrate evolutionary conservation of the exonic structure of its coding sequence, the extracellular domain structure and residues implicated in receptor binding, but the role of the longer cytoplasmic tail in avian PD ‐L1 proteins remains to be determined.