1988 Fiscal Year Final Research Report Summary
Mechanism of gene expression by androgen receptor in rat and mouse submandibular glands
| Project/Area Number |
61480392
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Functional basic dentistry
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| Research Institution | Iwate Medical University |
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Principal Investigator |
OTA Minoru Iwate Medical University School of Dentistry professor, 歯学部, 教授 (70048255)
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| Co-Investigator(Kenkyū-buntansha) |
NEMOTO Yuko Iwate Medical University School of Dentistry postdoctoral fellow fellow of the J, 歯学部, P.D (10164667)
KYAKUMOTO Seiko Iwate Medical University School of Dentistry research associate, 歯学部, 助手 (90118274)
KUROKAWA Riki Iwate Medical University School of Dentistry research associate, 歯学部, 助手 (70170107)
NEMOTO Takayuki Iwate Medical University School of Dentistry assistant professor, 歯学部, 講師 (90164665)
SATO Nobuko Iwate Medical University School of Dentistry associate professor, 歯学部, 助教授 (00048399)
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| Project Period (FY) |
1986 – 1988
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| Keywords | Androgen / Androgen Receptor / Submandibular Glands / Mouse / Rat / Nucleus / タンパク質 / クロマチン / 核 |
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| Research Abstract |
Conversion of steroid receptors from the nontransformed to transformed state, called transformation, is thought to be a key process of the steroid hormone action. Transformed receptors activate the specific genes in target cells. Transformation of steroid hormone receptor from a DNA-unbound state to a DNA-bound state can be induced by brief heating, exposure to salt, or ATP, and gel chromatography. IN general, nontransformed receptor is precipitated selectively by the addition of protamine sulfate. We found that the component responsible for the interection between the nontransformed receptor and protamine is an 88-kDa protein and this 88-kDa protein is almost the same as those of heat-shock protein 90 of hela cells and yeast for the amino acid composition.
The steroid-transformed receptor complex interacts with nuclear acceptor sites, but it remains unclear how the structure of chromatin is changed for gene expression. Cytosol androgen receptor prelabeled with [^3H]androgen interacted with the crude nuclei in mouse submandibular gland and activation of the receptor was prerequisite for this interaction. After in vivo administration of [^3H]androgen to female mice, redioactivities were found in the nuclei purified from submandibular gland tissues and the [^3H]androgen-labeled purified nuclei were further digested with micrococcal nuclease. the androgen receptor was found in solubilized, active chromatin fractions which contained mono- and dinucleosomes. By an in vitro exchange assay, endogenous androgen-receptor complexes associated with chromatin binding sites in intact males were found in the solubilized fraction after micrococcal nuclease digestion, whereas such complexes were not found in females. These results suggest that the androgen receptors translocated to the nuclei and became associated with chromatin and that this association preferentially sensitive to micrococcal nuclease.
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