Switching of melanocyte pigmentation associated with pituitary pars intermedia tumors in Rb+/- and p27-/- female mice with yellow pelage.
Comp Med
; 53(1): 75-80, 2003 Feb.
Article
en En
| MEDLINE
| ID: mdl-12625510
ABSTRACT
As an incidental finding in a study of mammary tumorigenesis, two lines of genetically engineered mice were observed to develop pigmentation changes of the fur. Mice with targeted mutations of the Rb1 (Rb) and Cdkn1b (p27kip1) genes were crossed from C57BL/6 (black coat color; eumelanin) and 129Sv (wild-type agouti coat color) backgrounds, respectively, to one with a dominant yellow coat color (phaeomelanin) carrying a transgene for Agouti under a keratinocyte specific promoter. Both Rb+/- and p27-/- mice developed pituitary tumors of the pars intermedia that were associated with a switch to black (eumelanic) fur but were not observed in sibling Rb+/+ and p27+/+ mice. This phenomenon was observed first in the vibrissae and, subsequently one to two weeks later, as periorbital and dorsal patches, and was associated with pituitary lesions larger than four millimeters in the longest dimension. In Rb+/- mice, pigmentation change preceded a moribund state attributable to the tumors by two to four weeks, whereas in p27-/- mice, the pigmentation alteration was earlier, more gradual, and prolonged. The switch from phaeomelanin to eumelanin in the fur is most likely due to out-competition of the agouti gene product by alpha-melanocyte-stimulating hormone from the pituitary tumors, an effect masked in black or agouti mice.
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Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Neoplasias Hipofisarias
/
Color del Cabello
/
Pigmentación
/
Proteína de Retinoblastoma
/
Proteínas de Ciclo Celular
/
Proteínas Supresoras de Tumor
/
Melanocitos
Tipo de estudio:
Risk_factors_studies
Límite:
Animals
Idioma:
En
Revista:
Comp Med
Asunto de la revista:
MEDICINA
/
MEDICINA VETERINARIA
Año:
2003
Tipo del documento:
Article
País de afiliación:
Estados Unidos