The dose dependence of glucocorticoid-inducible gene expression results from changes in the number of transcriptionally active templates

Minoru S.H. Ko, Hiromitsu Nakauchi, Naomi Takahashi

Research output: Contribution to journalArticlepeer-review

170 Citations (Scopus)

Abstract

Glucocorticoid hormones induce the transcription of genes having glucocorticoid response elements in a dose dependent manner. To determine whether this dose dependence represents a response of individual templates or of the mass of templates, we introduced a bacterial β-galactosidase gene linked to the glucocorticoid-indudble enhancer/promoter of the mouse mammary tumor virus (MTV) into Ltk- cells and obtained stable transformants containing a single or a few templates per cell. Visual inspection and flow cytometry analysis by enzyme histochemistry assay for β-galactosidase revealed that individual cells showed very heterogeneous β-galactosidase activity after 48 h induction with dexamethasone. When the glucocorticoid concentration was increased, an increasing cell population producing β-galactosidase was observed. These phenomena were probably not due to heterogeneity of template copy number or to a predetermined cellular state among individual cells, since cells forming a single small colony gave similar results. This was also supported by data showing that recloned cells retained both their responsiveness to the glucocorticoid hormone and their digestion pattern in Southern blotting analyses. These results indicate that the dose dependent increase of glucocorticoid-inducible gene expression is caused by an increase in the number of transcriptionally active templates.

Original languageEnglish
Pages (from-to)2835-2842
Number of pages8
JournalEMBO Journal
Volume9
Issue number9
Publication statusPublished - 1990
Externally publishedYes

Keywords

  • Flow cytometry analysis
  • Gene expression regulation
  • Glucocorticoid hormone
  • Individual template assay
  • Mouse mammary tumor virus

ASJC Scopus subject areas

  • General Biochemistry,Genetics and Molecular Biology
  • General Immunology and Microbiology
  • Molecular Biology
  • General Neuroscience

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