Methylation and expression of rat kappa-casein gene in normal and neoplastic rat mammary gland.
Cancer Res
; 45(3): 1291-5, 1985 Mar.
Article
en En
| MEDLINE
| ID: mdl-3971374
ABSTRACT
The kappa-casein mRNA was evaluated in the rat mammary gland during functional differentiation and neoplastic growth. Using a dot-blot assay, the mRNA was barely detectable in the virgin gland; it steadily increased from the onset of gestation and leveled off during lactation. In rat mammary tumors, either primary (7,12-dimethylbenz(a)anthracene-induced) or transplanted (MTW9), the level of kappa-casein mRNA was about 2.5-fold lower than in the lactating gland, but an extensive variation among individual tumors was observed. There was no detectable kappa-casein mRNA in rat liver. In the mammary gland of virgin, 10-day pregnant, and nonlactating females, the DNA sequences within and/or around the kappa-casein gene were found to be hypermethylated at the HpaII-MspI sites as compared to 10-day lactating females. In the two tumors studied, the kappa-casein gene was partially methylated at the same sites. Prolactin treatment induced kappa-casein gene expression in the virgin rat mammary gland but did not result in a change of the methylation status at the HpaII-MspI sites. Under similar conditions of prolactin treatment, however, the methylation of the Sau96I sites was reduced, and an inverse correlation between the onset of kappa-casein gene methylation and kappa-casein gene expression was evident in both the virgin gland and the tumors. Thus, the expression of kappa-casein was found to be inversely correlated with the extent of methylation of the kappa-casein gene, except in the case of the prolactin-stimulated virgin gland.
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Banco de datos:
MEDLINE
Asunto principal:
ADN de Neoplasias
/
Caseínas
/
Regulación de la Expresión Génica
/
Glándulas Mamarias Animales
/
Neoplasias Mamarias Experimentales
Límite:
Animals
Idioma:
En
Año:
1985
Tipo del documento:
Article