A possible involvement of melanocortin 3 receptor in the regulation of adrenal gland function in the chicken.
The melanocortin 3 receptor (MC3-R) in the melanocortin receptor family has been identified as a neural receptor subtype mainly expressed in the brain in mammals. We report here the isolation of the chicken gene for MC3-R, CMC3, displaying different tissue distribution from mammalian counterparts. The CMC3 gene was found to be a single copy gene encoding a 325 amino acid protein, sharing 75.3-76.8% identity with mammalian counterparts. When assessed by RT-PCR, the CMC3 mRNA was not detected in the brain but was exclusively expressed in adrenal glands, where Agouti-related protein/Agouti-related transcript (AGRP/ART), a newly identified endogenous antagonist of MC3-R, is expressed in mammals, raising the possibility that the CMC3 plays a role in complicated regulation of the gland function by melanocortins and AGRP/ART in the chicken. Noteworthy, MC1-R gene was found to be a quite unique member of the chicken MC-R family with regard to GC content and codon usage. It may reflect as yet unidentified evolutionary pressure operating specifically on the gene.
Takeuchi
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S
Department of Biology, Faculty of Science, Okayama University, Japan. stakeuch@cc.okayama-u.ac.jp
Takahashi
S
S
D000311:Adrenal Glands / Q000502:physiology*; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002645:Chickens / Q000235:genetics* / Q000502:physiology*; D004247:DNA / Q000235:genetics; D005260:Female; D015870:Gene Expression; D008297:Male; D008322:Mammals; D051379:Mice; D008969:Molecular Sequence Data; D010802:Phylogeny; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D044104:Receptor, Melanocortin, Type 3; D018043:Receptors, Corticotropin / Q000235:genetics* / Q000502:physiology*; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution