Hormonal regulation of phosphoenolpyruvate carboxykinase gene expression is mediated through modulation of an already disrupted chromatin structure

Journal Article · Wed Mar 01 04:00:00 EST 1989 · Molecular and Cellular Biology; (USA)

DOI:https://doi.org/10.1128/MCB.9.3.1289· OSTI ID:5643378

Ip, Y T; Granner, D K; Chalkley, R ^[1]

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1. Vanderbilt Univ., Nashville, TN (USA). School of Medicine

The authors 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. The authors 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.

• OSTI ID: 5643378
• Journal Information: Molecular and Cellular Biology; (USA), Journal Name: Molecular and Cellular Biology; (USA) Vol. 9:3; ISSN MCEBD; ISSN 0270-7306
• Country of Publication: United States
• Language: English

Related Subjects

550200* -- Biochemistry
59 BASIC BIOLOGICAL SCIENCES
AMP
ANIMALS
BIOLOGICAL PATHWAYS
CELL CULTURES
CHEMICAL REACTIONS
DISEASES
ENZYMES
GENE REGULATION
GENE REPRESSORS
GENES
HEPATOMAS
HORMONES
INSULIN
MAMMALS
METHYLATION
NEOPLASMS
NUCLEOPROTEINS
NUCLEOTIDES
ORGANIC COMPOUNDS
PEPTIDE HORMONES
PHENOTYPE
PHOSPHORUS-GROUP TRANSFERASES
PHOSPHOTRANSFERASES
PROTEINS
RATS
RODENTS
SPECIFICITY
TRANSCRIPTION
TRANSFERASES
VERTEBRATES