title: Conserved distal promoter of the agouti signaling protein (ASIP) gene controls sexual dichromatism in chickens.
abstract: Brilliant plumage is typical of male birds, thus sexual plumage dichromatism is seen in many avian species; however, the molecular mechanism underlying this remains unclear. The agouti signaling protein (ASIP) is a paracrine factor that stimulates yellow/red pigment (pheomelanin) synthesis and inhibits black/brown pigment (eumelanin) synthesis in follicular melanocytes. In mammals, the distal promoter of the ASIP gene acts exclusively on the ventral side of the body to create a countershading pigmentation pattern by stimulating pheomelanin synthesis in the ventrum. Here, we examined the role of the distal ASIP promoter in controlling estrogen-dependent sexual dichromatism in chickens. Reverse-transcription polymerase chain reaction analyses revealed that ASIP class 1 mRNAs transcribed by the distal promoter were expressed exclusively on the ventral side of chicks and adult females displaying countershading. In showy adult males, the ASIP class 1 mRNAs were expressed in gold-colored ornamental feathers grown on the back. In the presence of estrogen, males molted into female-like plumage and ASIP class 1 mRNAs expression was altered to female patterns. These results suggest that the distal ASIP promoter produces countershading in chicks and adult females, similar to the ventral-specific ASIP promoter in mammals. In addition, the class 1 promoter plays an important role for creating sexual plumage dichromatism controlled by estrogen. This is the first evidence for a pigmentation gene having been modified in its expression during evolution to develop phenotypic diversity between individuals of different sexes.
authors.affiliation: Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushimanaka, Kitaku, Okayama 700-8530, Japan.
authors.forename: Eri
authors.initials: E
authors.lastname: Oribe
authors.forename: Ayaka
authors.initials: A
authors.lastname: Fukao
authors.forename: Chihiro
authors.initials: C
authors.lastname: Yoshihara
authors.forename: Misa
authors.initials: M
authors.lastname: Mendori
authors.forename: Karen G
authors.initials: KG
authors.lastname: Rosal
authors.forename: Sumio
authors.initials: S
authors.lastname: Takahashi
authors.forename: Sakae
authors.initials: S
authors.lastname: Takeuchi
mesh_terms: D054366:Agouti Signaling Protein / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D000818:Animals; D002645:Chickens / Q000235:genetics / Q000254:growth & development / Q000378:metabolism / Q000502:physiology; D017124:Conserved Sequence / Q000235:genetics; D004967:Estrogens / Q000494:pharmacology; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D008297:Male; D008954:Models, Biological; D010641:Phenotype; D010858:Pigmentation / Q000187:drug effects / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000187:drug effects / Q000235:genetics*; D012733:Sex Differentiation / Q000187:drug effects / Q000235:genetics*; D012741:Sexual Maturation / Q000187:drug effects / Q000235:genetics / Q000502:physiology
chemical_list: D054366:Agouti Signaling Protein; D004967:Estrogens