Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.1.21 (thymidine kinase)
 7,561 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The 230-kD bullous pemphigoid antigen is a hemidesmosomal protein of the cutaneous basement membrane zone. We have previously cloned overlapping cDNAs corresponding to the human 230-kD bullous pemphigoid antigen gene (BPAG1), located at the human chromosomal locus 6p11-12. Utilizing the cDNA clones, a genomic DNA lambda FIX II phage library was screened. Seven over-lapping genomic clones, spanning approximately 20 kb, were isolated. These clones were shown to contain the entire approximately 9-kb coding sequence of BPAG1, and it consisted of 22 separate exons which varied from 78 to 2,810 bp in size. Elucidation of 2.6 kb of 5'-flanking DNA was found to contain several putative transcriptional response elements, and development of promoter chloramphenicol acetyltransferase (CAT) reporter gene constructs allowed identification of putative cis-elements which confer keratinocyte-specific expression to the gene. In particular, a putative AP2-binding sequence (KRE2) in the position -(1,786-1778) was shown to be responsible for marked enhancement of the endogenous promoter, as well as of a heterologous thymidine kinase/CAT construct, activity in normal human keratinocytes. Normal human keratinocyte nuclear extracts contained a protein, designated as KTP1, which complexed with the KRE2 oligomer by gel mobility shift assays. UV cross-linking and Southwestern analysis suggested that KTP1 is a DNA-binding protein clearly distinct from AP2, and this protein may be responsible for the basal keratinocyte-specific expression of the BPAG1 gene.
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PMID:Molecular biology of the 230-kD bullous pemphigoid antigen. Cloning of the BPAG1 gene and its tissue-specific expression. 804 59

The 230-kDa bullous pemphigoid antigen (BPAG1) is an integral component of hemidesmosomes. We have previously reported that interferon-gamma (IFNgamma) inhibits the transcription of the BPAG1 gene (1). Here we investigated the target sequences of IFNgamma-signal transduction pathway in the BPAG1 promoter in epidermal keratinocytes. Transient transfections with 5'-deletion constructs of BPAG1 promoter-luciferase reporter gene plasmids in cultured normal human epidermal keratinocytes (NHEK) allowed us to narrow the DNA region containing IFNgamma inhibitory element (IGIE) to between -1 and -89, upstream from the transcription initiation site (+1). Homology search in this region identified a chimeric sequence, consisting of IFN-stimulated responsive element (ISRE) with a partial 7-bp sequence of IFNgamma activation site (GAS), as identified in the guanylate-binding protein (GBP) gene, inserted at its center. Functional analysis of IGIE, inserted in front of the heterologous thymidine kinase promoter, indicated that IGIE acts as a down-regulatory element of the promoter through IFNgamma-dependent signal pathway. Transient transfection studies with BPAG1 promoter-reporter gene constructs containing mutated IGIE (with TT to GG transversions in the region of 5'ISRE, GAS, and 3'ISRE) demonstrated that disruption of the ISRE sequences, but not GAS, markedly suppressed the BPAG1 basal promoter activity and resulted in attenuated IFNgamma response in keratinocytes. Our findings provide novel insight into the mechanism of IFNgamma regulation in keratinocyte differentiation and proliferation.
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PMID:Interferon-gamma down-regulates expression of the 230-kDa bullous pemphigoid antigen gene (BPAG1) in epidermal keratinocytes via novel chimeric sequences of ISRE and GAS. 1651 78