Hormonal regulation of phosphoenolpyruvate carboxykinase gene expression is mediated through modulation of an already disrupted chromatin structure.
Open Access
- 1 March 1989
- journal article
- Published by Taylor & Francis in Molecular and Cellular Biology
- Vol. 9 (3), 1289-1297
- https://doi.org/10.1128/mcb.9.3.1289
Abstract
We used indirect end labeling to identify a series of five hypersensitive (HS) sites in the phosphoenolpyruvate carboxykinase (PEPCK) gene in H4IIE rat hepatoma cells. These sites were found at -4800 base pairs (bp) (site A), at -1300 bp (site B), over a broad domain between -400 and -30 bp (site C), at +4650 bp (site D), and at +6200 bp (site E). Sites A to D were detected only in cells capable of expressing the PEPCK gene, whereas site E was present in all of the cells examined thus far. The HS sites were present in H4IIE cells even when transcriptional activity was reduced to a minimum by treatment with insulin. Stimulation of transcription by a cyclic AMP analog to a 40-fold increase over the insulin-repressed level did not affect the main features of the HS sites. Furthermore, increased transcription did not disrupt the nucleosomal arrangement of the coding region of the gene, nor did it affect the immediate 5' region (site C), which is always nucleosome-free. In HTC cells, a rat hepatoma line that is hormonally responsive but unable to synthesize PEPCK mRNA, the four expression-specific HS sites were totally absent. Our experimental results also showed that, although there is a general correlation between lack of DNA methylation and transcriptional competence of the PEPCK gene, the role, if any, of methylation in the regulation of PEPCK gene activity is likely to be exerted at very specific sites.Keywords
This publication has 38 references indexed in Scilit:
- Genomic footprinting reveals cell type-specific DNA binding of ubiquitous factorsCell, 1987
- DNase I-hypersensitive sites associated with expression and hormonal regulation of mouse C4 and Slp genes.Proceedings of the National Academy of Sciences, 1987
- Affinity chromatographic purification of nucleosomes containing transcriptionally active DNA sequencesJournal of Molecular Biology, 1987
- Specific sets of DNase I-hypersensitive sites are associated with the potential and overt expression of the rat albumin and alpha-fetoprotein genes.Proceedings of the National Academy of Sciences, 1987
- Core Particle, Fiber, and Transcriptionally Active Chromatin StructureAnnual Review of Cell Biology, 1986
- Protein-DNA interactions and nuclease-sensitive regions determine nucleosome positions on yeast plasmid chromatinJournal of Molecular Biology, 1986
- Nucleosomal instability and induction of new upstream protein-DNA associations accompany activation of four small heat shock protein genes in Drosophila melanogaster.Molecular and Cellular Biology, 1986
- SELECTED TOPICS IN CHROMATIN STRUCTUREAnnual Review of Genetics, 1985
- Interaction of specific nuclear factors with the nuclease-hypersensitive region of the chicken adult β-globin gene: Nature of the binding domainCell, 1985
- Nucleosome disruption precedes transcription and is largely limited to the transcribed domain of globin genes in murine erythroleukemia cellsJournal of Molecular Biology, 1985