Contribution of a Nuclear Factor 1 Binding Site to the Glucocorticoid Regulation of the Cytosolic Aspartate Aminotransferase Gene Promoter

Abstract

Two regions of the cAspAT gene promoter mediate the glucocorticoid regulation of this gene in the Fao hepatoma cell line. The proximal region was localized by deletion studies and stable transfections in the Fao cells to the sequence ؊553/؊398. This region includes the glucocorticoid-responsive element (GRE) A sequence, which consists of two overlapping GREs and which can mediate the glucocorticoid regulation of a heterologous promoter. DNase I footprinting studies have shown that a site 80 base pairs upstream of the GRE A was protected by liver and brain nuclear extracts (site P 8 ). The binding was displaced by an excess of an oligonucleotide containing a typical NF 1 binding site and by NF 1 -specific antibodies. In electrophoretic mobility shift assay using the P 8 oligonucleotide as a probe, several complexes were formed. Most complexes were common to liver and brain but were less abundant when testis extracts were used. At least one complex was specific to the liver. All complexes, with the exception of two, were competed for by the NF 1 oligonucleotide. Furthermore, the sequence of the P 8 site showed a 7/9-base pair homology with a typical NF 1 site. A mutation of the P 8 site, which prevents the binding of NF 1 -like proteins to it, considerably decreases the regulation of the cAspAT promoter fragment by glucocorticoids. Surprisingly, the basal activity of the mutant promoter was increased 2-fold. Thus, the regulation of the cAspAT gene promoter is mediated by a regulatory unit comprising the GRE A and a NF 1 binding site.

CREB Binding Protein Coordinates the Function of Multiple Transcription Factors Including Nuclear Factor I to Regulate Phosphoenolpyruvate Carboxykinase (GTP) Gene Transcription

“…More recently, NFI has been implicated in transcriptional control of genes of physiological importance. For example, NFI is involved in glucocorticoid receptor-mediated transcriptional response of the gene for mouse mammary tumor virus (44) and aspartate aminotransferase (45). It is also a negative modulator of transcription of the gene for L-type pyruvate kinase (46).…”

The Genomic Response of Skeletal Muscle to Methylprednisolone Using Microarrays: Tailoring Data Mining to the Structure of the Pharmacogenomic Time Series

“…All remaining animals received a single 50 mg/kg dose of MPL sodium succinate (Pharmacia-Upjohn Company, Kalamazoo, MI, USA) via the cannula over 30 s. Rats (3) were sacrificed by exsanguinations under anesthesia at 0.25, 0.5, 0.75, 1, 2, 4, 5, 5. 5,6,7,8,12,18,30,48 and 72 h after dosing. The sampling time points were selected based on previous studies describing glucocorticoid response dynamics and enzyme induction in skeletal muscle and liver.…”

“…However, there are a large number of genes whose transcription is altered indirectly by glucocorticoids. In these cases, glucocorticoids alter the expression or function of other transcription factors, which in turn alter the transcription of other genes [13,[18][19][20][21][22]. Although still not entirely understood, the phenomena of muscle wasting and insulin resistance clearly involve temporal cascades of changes in the expression of a multiplicity of genes [2][3][4][5]19,[23][24][25][26].…”

Regulation of S100A8 by Glucocorticoids

“…5A), and although this contains no classical GRE, candidate elements include AP-1 motifs (Ϫ164, Ϫ102, Ϫ18) and an NF1 motif (Ϫ58). Because NF1 mediates induction of several genes by GCs (34,35), the NF1 motif was mutated at Ϫ58 bp (pCP-178/0NF1). Fig.…”