Avian IFN-gamma genes: sequence analysis suggests probable cross-species reactivity among galliforms.
Little is known about the evolution of cytokines in non-mammalian systems. To address this problem, we attempted to clone the gene for interferon-gamma (IFN-gamma) from a variety of avian species using oligonucleotide primers based on the sequence of the chicken IFN-gamma gene. The coding sequence and partial intron sequences were determined for four species, namely guinea fowl, ring-necked pheasant, Japanese quail, and turkey. To obtain sequence information on the gene extremities, a modified 5' and 3' RACE protocol was used. The sequence information showed that the coding regions of the IFN-gamma gene are highly conserved among the species studied (93.5%-96.7% and 87.8%-97.6% at the nucleotide and peptide levels, respectively) and are more conserved at the amino-terminal region (exons 1 and 2) than the carboxyl-terminal (exons 3 and 4). This high degree of overall identity at the predicted primary amino acid sequence level of the protein, including the deduced IFN-gamma receptor binding motifs, suggests that IFN-gamma may be cross-reactive among these species. Phylogenetic analysis shows that the similarity of the avian IFN-gamma sequences parallels the presumed evolutionary relationships between the species.
Institute for Animal Health, Compton, Berkshire, UK. pete.kaiser@bbsrc.ac.uk
P
P
Kaiser
D
D
Sonnemans
L M
LM
Smith
D000595:Amino Acid Sequence; D000818:Animals; D000917:Antibody Formation / Q000235:genetics; D001483:Base Sequence; D001717:Birds / Q000235:genetics*; D003001:Cloning, Molecular; D019143:Evolution, Molecular; D005815:Genetic Code; D016678:Genome; D007371:Interferon-gamma / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D011336:Probability; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D013045:Species Specificity
D007371:Interferon-gamma