Cooperative interactions between the GRP78 enhancer and promoter elements in hamster fibroblasts.
A non-tissue-specific enhancer derived from the promoter of the rat 78-kDa glucose-regulated protein (GRP78)-coding gene was tested for its ability to stimulate the activity of its homologous promoter and two heterologous promoters (simian virus 40 and mouse mammary tumor virus). Single and double copies of the enhancer were inserted at positions 5' and 3' of the cat-expression vectors under the direction of the above promoters. The recombinant plasmids were transfected into hamster fibroblast K12 cells and assayed for chloramphenicol acetyl transferase activity under induced and non-induced conditions. We report that the GRP78 enhancer (i) exhibits strong cooperative interactions with its homologous promoter; (ii) can activate and confer a calcium ionophore (A23187) inducibility to heterologous promoters in an orientation-independent manner; (iii) prefers the 5' over the 3' location and; (iv) is dosage dependent in that two copies are twice as active as a single unit.
Kim
Y K
YK
Department of Biochemistry, University of Southern California School of Medicine, Los Angeles 90033.
Lee
A S
AS
D000818:Animals; D001483:Base Sequence; D000001:Calcimycin; D002352:Carrier Proteins / Q000096:biosynthesis / Q000235:genetics*; D002460:Cell Line; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics; D006224:Cricetinae; D000091342:Endoplasmic Reticulum Chaperone BiP; D004742:Enhancer Elements, Genetic; D005347:Fibroblasts / Q000378:metabolism; D005784:Gene Amplification; D005796:Genes; D006360:Heat-Shock Proteins; D008324:Mammary Tumor Virus, Mouse / Q000235:genetics; D018832:Molecular Chaperones; D010957:Plasmids; D011401:Promoter Regions, Genetic / Q000187:drug effects; D051381:Rats; D013539:Simian virus 40 / Q000235:genetics; D014158:Transcription, Genetic; D014162:Transfection
D002352:Carrier Proteins; D000091342:Endoplasmic Reticulum Chaperone BiP; D006360:Heat-Shock Proteins; C000717248:Hspa5 protein, mouse; D018832:Molecular Chaperones; D000001:Calcimycin; D015500:Chloramphenicol O-Acetyltransferase