The cytokine response element of the rat alpha 1-acid glycoprotein gene is a complex of several interacting regulatory sequences.
Expression of the rat alpha 1-acid glycoprotein gene is stimulated by interleukin-1 (IL-1) and interleukin-6 (IL-6) and is synergistically enhanced by the combination of the two. The distal regulatory element (DRE), a 142-base-pair (bp) sequence located 5 kilobase pairs upstream of the transcriptional start site, appears to be crucial for this cytokine response. The cytokine-specific regulatory sequences within the DRE have been identified by inserting individual DRE subregions, selected combinations of these, or a few linker mutated fragments into a plasmid containing an enhancerless simian virus 40 promoter linked to the chloramphenicol acetyltransferase gene. The regulatory activity was determined in transiently transfected human and rat hepatoma cells. The IL-1 response region was confined to the 5'-most 62 bp of the DRE, and its function seemed to depend on at least two separate components. The same region was also responsive to phorbol ester treatment. The IL-6 regulatory function was dependent on a 54-bp sequence located within the 3' half of the DRE. When the IL-1 response region was recombined with the IL-6 regulatory region of the DRE or with IL-6 response elements of other plasma protein genes, a strong cooperative action by IL-1 and IL-6 was achieved. The functional DRE sequences were recognized by nuclear proteins extracted from rat liver and hepatoma cells. However, no cytokine-inducible binding activity was detectable, which suggests that transcriptional regulation through the DRE might be controlled by posttranslational modification of constitutively bound trans-acting factors.
Department of Molecular and Cellular Biology, Roswell Park Cancer Institute, Buffalo, New York 14263.
K A
KA
Won
H
H
Baumann
D000818:Animals; D001483:Base Sequence; D001685:Biological Factors / Q000494:pharmacology*; D002460:Cell Line; D016207:Cytokines; D004268:DNA-Binding Proteins / Q000302:isolation & purification / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects*; D005796:Genes / Q000187:drug effects*; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology*; D015850:Interleukin-6 / Q000494:pharmacology*; D008099:Liver / Q000378:metabolism; D008114:Liver Neoplasms, Experimental / Q000378:metabolism; D008969:Molecular Sequence Data; D009961:Orosomucoid / Q000235:genetics*; D010957:Plasmids; D051381:Rats; D011994:Recombinant Proteins / Q000494:pharmacology; D012045:Regulatory Sequences, Nucleic Acid; D012689:Sequence Homology, Nucleic Acid; D014162:Transfection
D001685:Biological Factors; D016207:Cytokines; D004268:DNA-Binding Proteins; D007375:Interleukin-1; D015850:Interleukin-6; D009961:Orosomucoid; D011994:Recombinant Proteins