Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0022575 (keratoconjunctivitis sicca)
 772 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The RNA-dependent protein kinase (PKR) is inducible by interferon (IFN) and is implicated in the antiviral and antiproliferative actions of IFN. We have now isolated human genomic clones that contain the promoter region required for transcription of the Pkr gene. Transient transfection analyses, using chloramphenicol acetyltransferase (CAT) as the reporter in constructs possessing various 5'-flanking fragments of the Pkr gene, led to the identification of a functional TATA-less promoter that directed IFN-inducible transcription of CAT. Sequence determination and deletion analysis of the promoter region revealed an element (5'GGAAAACGAAACT3') involved in IFN inducibility that corresponds to the consensus sequence of the IFN-stimulated response element (ISRE). Comparison of the promoter sequence of the human Pkr gene to that of the mouse homolog identified a novel element (5'GGGAAGGCGGAGTCC3') immediately upstream of the ISRE element which so far is unique to the human and mouse Pkr gene promoters. We have designated this new motif as KCS, for kinase conserved sequence. Deletion and substitution mutants of the Pkr promoter region showed that the ISRE element was required for transcriptional induction by type I IFN, whereas the KCS motif increased promoter activity mediated by the ISRE. Additional potential regulatory cis-elements were identified in the human Pkr promoter that are commonly associated with growth control regulation and differentiation. Other than the ISRE and novel KCS elements, the overall organization of potential binding sites for transcription factors was not well conserved between the IFN-inducible promoters of the human and mouse Pkr genes. The strict conservation of sequence, distance, and position of KCS, relative to ISRE, together with mutagenesis results, suggest an important functional role for the newly recognized KCS motif.
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PMID:Isolation of the interferon-inducible RNA-dependent protein kinase Pkr promoter and identification of a novel DNA element within the 5'-flanking region of human and mouse Pkr genes. 900 65

The PKR protein kinase is an important regulator of viral mRNA translation. A approximately 50-kb gene (Pkr) encodes the human PKR protein that is inducible by interferon (IFN). The Pkr promoter region has a novel 15-bp DNA element designated as KCS required for transcriptional activity that is located 4 bp upstream of a 13-bp IFN-stimulated response element (ISRE) that confers inducibility by type I IFN. We have carried out a systematic analysis of the 5' flanking region of the human Pkr gene to define how the novel KCS element acts to affect basal as well as IFN-inducible transcription. Electrophoretic mobility shift analyses (EMSA) revealed that nuclear proteins bound selectively to the KCS element in a manner that was not dependent upon either IFN treatment or protein binding at the adjacent ISRE element. KCS protein binding activity in vitro correlated with activation of transcription in vivo in transient transfection assays. Competitionsupershift EMSA assays revealed that multiple proteins were involved in bandshift complex formation with KCS, one of which was identified as factor Sp1. In addition to the positive regulatory domain containing the KCSISRE elements, a negative regulatory domain (NRD) was identified within a 40-bp region positioned approximately 400-bp upstream of the KCSISRE elements. Deletion and substitution mutations indicated that the NRD negatively affected Pkr transcription by a mechanism dependent upon the KCS element. These results define novel positivenegative regulatory domains within the Pkr promoter that function through the KCS element to affect basalIFN-inducible transcription of Pkr.
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PMID:Mechanism of interferon action: functional characterization of positive and negative regulatory domains that modulate transcriptional activation of the human RNA-dependent protein kinase Pkr promoter. 992 85

The RNA-dependent protein kinase (PKR) is implicated in the antiviral and antiproliferative actions of interferon (IFN). As an extension of our structural characterization of the exon-intron organization of the mouse Pkr gene, we now have isolated and characterized the mouse Pkr promoter region required for IFN-inducible transcription. Transient transfection analyses, using reporter constructs possessing various 5'-flanking fragments of the Pkr gene, led to the identification of a functional IFN-inducible promoter. A single IFN-stimulated response element (ISRE) was present in a minimal 44-nt TATA-less promoter identified by deletion analysis; the 13-nt ISRE differed from previously described ISRE elements in that the 3'-nt was a purine instead of a pyrimidine. The sequence immediately upstream of the ISRE possessed the 15-nt KCS element that was exactly conserved in sequence and position between the mouse and human Pkr promoters. A single gamma IFN-activated sequence (GAS)-like element and multiple recognition sites for factors including NF-kappaB and NF-IL6 involved in responses to various cytokine and hormone signals in inflammatory responses were also present in the 5'-flanking region. Northern blot analysis showed efficient IFN-alpha induced accumulation of 2.4kb, 4.5kb and approx. 6kb Pkr transcripts, but neither IFN-gamma nor IL-6 induced detectable Pkr mRNA accumulation in L cells.
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PMID:Mouse interferon-inducible RNA-dependent protein kinase Pkr gene: cloning and sequence of the 5'-flanking region and functional identification of the minimal inducible promoter. 1076 60