Molecular Histo-cytochemical Analysis of Gene Expression Regulation by Artificial Control of Transcription Factors

点击翻译按钮获取中文摘要

1.Effects of exogenously administered estrogenic substances on prolactin(PRL) gene expression through the transcription factors, estrogen receptors(ERs) and Pit-1,were examined. PRL-and Pit-1-positive cells were increased, whereas FSH/LH-positive cells were decreased in the pituitaries of mice treated with diethylstilbestrol(DES). ER α was localized in the nuclei of PRL and FSH/LH cells hi the control mice, whereas hi DES-treated mice ER α -positive PRL cells were decreased and ER β-positive PRL cells were induced and then increased instead. In ER α-knockout mice ER β was localized in PRL cell nuclei and population of ER β, PRL or FSH/LH positive cells was constant. Treatment of wild-type mice with DES seemed to increase PRL gene transcription with an increase of both Pit-1 and ER β as well as a decrease of ER α hi the PRL cell nuclei. It suggests that quantity and quality of the transcription factors are regulated by DES.2.We examined effects of artificial regulation on intranuclear distribution of the transcription factors in PRL producing GH3 culture cells. Pit-1 and ERs were localized to clarify whether PRL gene transcription was repressed when the double-stranded nucleotide sequences of PRL gene regulatory element (1P), which bind to Pit-1, were trans-inducted into the nuclei to block the 1P-binding sites. An autoclave retrieval was effective to enhance signals from the nuclear Pit-1 and ERs detected by Southwestern histochemistry and peroxidase-labeled antibody method, respectively, both at light- and electron microscopic levels. GH3 cells, in which Pit-1 and ER α were localized in the euchromatin region in the vicinity of the heterochromatin, possessed PRL. It appeared that Pit-1 and ER were distributed hi a definite nuclear region where the gene is expressed in GH3 cells. Optimal concentration and tune after the probe trans-induction were under examination.