Functional analysis of the KCS-like element of the interferon-inducible RNA-specific adenosine deaminase ADAR1 promoter

• Published in: Gene Vol. 304; no. C; pp. 143 - 149
• Main Authors: Markle, Danielle, Das, Sonali, Ward, Simone Visosky, Samuel, Charles E
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 30.01.2003
• Subjects: ADAR deaminase; Adenosine Deaminase - genetics; Antibodies - immunology; Antibodies - pharmacology; Base Sequence; Binding, Competitive - drug effects; Cell Line; Chloramphenicol O-Acetyltransferase - genetics; Chloramphenicol O-Acetyltransferase - metabolism; eIF-2 Kinase - genetics; Electrophoretic Mobility Shift Assay; Gene Expression Regulation - drug effects; Humans; Interferon; Interferons - pharmacology; Nuclear Proteins - metabolism; Oligonucleotides - genetics; Oligonucleotides - metabolism; Promoter Regions, Genetic - genetics; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - metabolism; Response Elements - genetics; RNA editing; RNA-Binding Proteins; Sp1 Transcription Factor - immunology; Sp1 Transcription Factor - metabolism; Transcriptional control; bp, basepair; IFN, interferon; RNA editing; ADAR1, gene encoding the double-stranded RNA adenosine deaminase; ADAR1, double-stranded RNA adenosine deaminase; KCS, kinase conserved sequence of the PKR promoter; ADAR deaminase; KCS-ℓ, KCS-like element of the human ADAR1 promoter; Transcriptional control; PKR, gene encoding the PKR kinase; ISRE, interferon-stimulated response element; PKR, the RNA-dependent eIF-2α protein kinase inducible by interferon; Interferon
• ISSN: 0378-1119; 1879-0038
• DOI: 10.1016/S0378-1119(02)01200-3

The ADAR1 gene encodes an RNA-specific adenosine deaminase that alters the functional activity of both viral and cellular RNAs by posttranscriptional adenosine-to-inosine RNA editing. The interferon (IFN) responsive PI promoter of the ADAR1 gene possesses an IFN-stimulated response element (ISRE) responsible for IFN-inducibility, as well as an adjacent upstream sequence, designated kinase conserved sequence-like (KCS-ℓ) element. The KCS-ℓ element is similar to the 15-bp KCS element so far unique to the human and mouse RNA-dependent PKR kinase gene promoters. The KCS element of the PKR kinase ( PKR) promoter is essential for both basal and IFN-inducible PKR promoter activity. We have now examined the functional properties of the KCS-ℓ element of the ADAR1 PI promoter. Electrophoretic mobility shift assays (EMSAs) detected constitutively expressed nuclear proteins that bound selectively to the ADAR1 KCS-ℓ element. Competition EMSA and antibody supershift assays indicated that ADAR1 KCS-ℓ-binding proteins shared some properties with PKR KCS-binding proteins. However, transient transfection analyses performed with ADAR1 PI promoter constructs possessing deletion and substitution mutant forms of the KCS-ℓ element revealed that the ADAR1 KCS-ℓ element was not essential for either basal or IFN-inducible promoter activity. Substitution of the ADAR1 KCS-ℓ element with the PKR KCS element increased both basal and inducible ADAR1 PI promoter activity. These results suggest that the KCS-ℓ element of the ADAR1 PI promoter is not functionally equivalent to the KCS element of the PKR promoter.