title: Neuroglobin, cytoglobin, and a novel, eye-specific globin from chicken.
abstract: Neuroglobin and cytoglobin are two recently discovered respiratory proteins of vertebrates. Here we report the first identification and expression analyses of these proteins in bird species. Neuroglobin from the domestic chicken Gallus gallus differs in approximately 30% from the mammalian proteins, but its genome structure shows the conservation of the B12.2, E11.0, and G7.0 intron positions. The chicken cytoglobin protein is shorter than the mammalian orthologs, from which it differs overall by approximately 25%, due to the absence of the C-terminal exon in the gene. Comparison of chicken and mammalian gene order shows that neuroglobin and cytoglobin are located on conserved syntenic chromosomal segments. While neuroglobin is expressed in the chicken's brain and eye, cytoglobin RNA was detected in all investigated tissues. In addition, a novel globin-type has been identified that is only expressed in the chicken's eye. The gene of this eye-globin contains the typical globin introns at B12.2 and G7.0. Phylogenetic analyses suggest that this globin is most closely related to the cytoglobin lineage. Although the function of this eye-globin remains presently uncertain, it adds an additional diversity to the vertebrate globin family.
authors.affiliation: Institute of Zoology, Johannes-Gutenberg University, D-55099 Mainz, Germany.
authors.forename: Dominik
authors.initials: D
authors.lastname: Kugelstadt
authors.forename: Mark
authors.initials: M
authors.lastname: Haberkamp
authors.forename: Thomas
authors.initials: T
authors.lastname: Hankeln
authors.forename: Thorsten
authors.initials: T
authors.lastname: Burmester
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002645:Chickens / Q000235:genetics* / Q000378:metabolism*; D017124:Conserved Sequence; D019143:Evolution, Molecular; D005914:Globins / Q000235:genetics* / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D000078787:Neuroglobin; D010802:Phylogeny; D012160:Retina / Q000378:metabolism*; D020539:Sequence Analysis, Protein; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D014714:Vertebrates
chemical_list: D009419:Nerve Tissue Proteins; D000078787:Neuroglobin; D005914:Globins