cAMP responsiveness of the bovine calpastatin gene promoter.
Previous studies have shown that transcription of the gene encoding bovine calpastatin, an inhibitor of the calcium-activated cysteine protease calpain, is upregulated following activation of cAMP-dependent signaling pathways. In this study, deletion and site-directed mutagenesis experiments were performed to identify cis elements conferring cAMP responsiveness. Heterologous promoter assays demonstrated that all cAMP-responsive cis elements were located within -102 nucleotides (nt) of transcription initiation. Deletion of an element (GTCA) at nt +13 that is identical to half of the palindromic cAMP-responsive element (TGACGTCA) identified in other cAMP-responsive gene promoters had no effect on the response of the calpastatin promoter to dibutyryl-cAMP, although a 67% reduction in basal promoter activity was observed. In contrast, two point mutations in a cis element at nt -76 (GTCA to aTCt) abolished cAMP responsiveness. These results demonstrate that the calpastatin promoter sequence between nt -1653 and +130 contains a single cAMP-responsive element (GTCA) located at nt -76, and suggest a direct molecular pathway by which activation of cAMP signaling could lead to increased calpastatin gene transcription and reduction in calpain-mediated proteolysis.
Cong
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M
Department of Biochemistry, University of Arizona, Tucson, AZ 85721, USA.
Goll
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DE
Antin
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D016475:3T3 Cells; D000818:Animals; D001483:Base Sequence; D003994:Bucladesine / Q000494:pharmacology; D002135:Calcium-Binding Proteins / Q000235:genetics*; D002154:Calpain / Q000378:metabolism; D002417:Cattle; D000242:Cyclic AMP / Q000378:metabolism*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000502:physiology; D051379:Mice; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D014158:Transcription, Genetic; D014162:Transfection
D002135:Calcium-Binding Proteins; D003994:Bucladesine; C033668:calpastatin; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D002154:Calpain