Characterization of adrenomedullin in birds.
Adrenomedullin (AM) is a multifunctional evolutionarily highly conserved peptide. Although its genomic and amino acid (aa) sequences are known in several mammalian species and in fish, the structure of the AM gene remains unknown in intermediate phyla, including birds. Here, we report the structure and aa sequence of the chicken (c) AM ortholog. The cAM gene is located at the short arm of chromosome 5, which shows high synteny with the short arm of human (h) chromosome 11, where hAM is located. Key sequences in the third intron have been conserved which allow for an alternative splicing mechanism, similar to the one found in mammals. The preprohormone contains two peptides with high homology to human proadrenomedullin N-terminal 20 peptide (PAMP) and hAM. We found through real-time PCR and immunocytochemistry cAM mRNA and peptide expression in a variety of chicken tissues, which parallel patterns observed for mammals, with the exception that cAM levels are almost non-detectable in brain. Similarly to mammals, cAM expression is upregulated under hypoxic conditions and following dexamethasone treatment. These data demonstrate a high degree of homology between the cAM gene and its mammalian ortholog and evolutionary conservation of the regulatory mechanisms controlling its expression.
Cell and Cancer Biology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA. zudairee@mail.nih.gov
Enrique
E
Zudaire
Natalia
N
Cuesta
Alfredo
A
Martínez
Frank
F
Cuttitta
D053607:Adrenomedullin; D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002645:Chickens; D003907:Dexamethasone / Q000494:pharmacology*; D006801:Humans; D000860:Hypoxia / Q000150:complications*; D007150:Immunohistochemistry; D010455:Peptides / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D015854:Up-Regulation / Q000187:drug effects
D010455:Peptides; D053607:Adrenomedullin; D003907:Dexamethasone