A single upstream glucocorticoid response element juxtaposed to an AP1/ATF/CRE-like site renders the chicken glutamine synthetase gene hormonally inducible in transfected retina.
The cis-acting element mediating glucocorticoid inducibility of the chicken glutamine synthetase gene has been identified. Transfection studies using intact embryonic chicken retinae and L6 myoblasts demonstrate that sequences located between 1,849 and 2,120 nucleotides upstream of the glutamine synthetase transcription start site are required to achieve hormonally inducible expression of the chloramphenicol acetyltransferase gene. Moreover, a 42-nucleotide fragment from this region provides a robust hormonal induction when positioned approximately 2 kilobases from the SV40 early promoter. A sequence containing 8 nucleotides in common with the 12-nucleotide consensus glucocorticoid response element is encoded within this element. DNase I footprinting experiments confirm that this consensus sequence provides the only binding sites for the glucocorticoid receptor within the DNA required for inducibility. Removal of 8 nucleotides that map outside of the footprinting region results in attenuation of the hormonal response in L6 myoblasts and abolition of the response in embryonic retinae. This deletion eliminates the sequence 5'CAGCGTCA3', a sequence that resembles the canonical cyclic AMP response element (CRE), activating transcription factor (ATF), and AP1 binding sites. These results suggest that the glucocorticoid receptor acts in collaboration with a member of the jun/fos/ATF/CREB family of transcription factors to mediate a strong glucocorticoid induction at a site 2.1 kilobases upstream of the glutamine synthetase transcription start site.
Division of Pharmacology, College of Pharmacy, Ohio State University, Columbus 43210.
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Zhang
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Young
D051696:Activating Transcription Factors; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D001798:Blood Proteins / Q000378:metabolism; D002642:Chick Embryo; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics; D017362:Cyclic AMP Response Element-Binding Protein; D016172:DNA Fingerprinting; D004268:DNA-Binding Proteins / Q000378:metabolism; D004790:Enzyme Induction / Q000235:genetics; D005938:Glucocorticoids / Q000378:metabolism*; D005974:Glutamate-Ammonia Ligase / Q000096:biosynthesis / Q000235:genetics*; D008969:Molecular Sequence Data; D010957:Plasmids; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012045:Regulatory Sequences, Nucleic Acid; D012160:Retina / Q000196:embryology / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism; D014162:Transfection
D051696:Activating Transcription Factors; D001798:Blood Proteins; D017362:Cyclic AMP Response Element-Binding Protein; D004268:DNA-Binding Proteins; D005938:Glucocorticoids; D016755:Proto-Oncogene Proteins c-jun; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; D015500:Chloramphenicol O-Acetyltransferase; D005974:Glutamate-Ammonia Ligase