Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.30.1 (S1 nuclease)
 3,660 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The expression in Escherichia coli of a cloned crystal protein gene from Bacillus thuringiensis was investigated through the use of fusions of the crystal protein gene promoter to beta-galactosidase and catechol oxidase genes. Analysis of deletion and insertion derivatives of the crystal protein gene promoter showed that a region of B. thuringiensis DNA located between 87 and 258 base pairs upstream from the transcription initiation site caused reduced transcription from this promoter. Insertion of Tn5 145 base pairs upstream from the transcription initiation site resulted in overproduction of the crystal protein. S1 nuclease mapping experiments failed to detect transcription from an outwardly directed promoter in Tn5, indicating that the overproduction resulted from the disruption or repositioning of the transcription-suppressing region.
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PMID:Expression of a cloned Bacillus thuringiensis crystal protein gene in Escherichia coli. 304 Jun 77

We have cloned and sequenced the human genomic DNA segments encoding the 5'-flanking region and the first two exons of the DOPAchrome tautomerase (DT)/tyrosinase-related protein 2 (TRP-2) gene. The DT gene is a member of the tyrosinase gene family and specifically expressed in melanin-producing cells. A transcriptional initiation site of the DT gene was identified by S1 nuclease-mapping and primer-extension analyses using RNA prepared from human pigmented melanoma cells. To study the mechanism for pigment cell-specific expression of the human DT gene, we analyzed the promoter function of its 5'-flanking region by transient expression assays. The fusion genes, containing the DT gene promoter upstream from a firefly luciferase reporter gene, were introduced into human pigmented melanoma cells and HeLa cells, and the pigment cell-specific promoter activity was evaluated by comparing the luciferase activity expressed in both cell lines. A series of 5' deletion studies of the human DT gene promoter revealed that the 32-bp element, located between -447 and -415, is sufficient to confer pigment cell-specific expression of a reporter gene on a homologous promoter, but not on a heterologous simian virus 40 promoter. Internal deletion studies using a homologous or a heterologous promoter revealed that the pigment cell-specific expression of a reporter gene mediated by the 32-bp element is dependent on the presence of another region of the DT gene spanning from -268 to -56, which was termed the proximal region. However, the proximal region by itself is not sufficient to confer cell type-specific expression. These results indicate that the presence of two regulatory regions, the 32-bp element and the proximal region, is required for pigment cell-specific expression of the DT gene. Both regulatory regions contain a CANNTG motif, a well known binding site for a large family of transcription factors possessing a basic helix-loop-helix structure.
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PMID:Cloning of the human DOPAchrome tautomerase/tyrosinase-related protein 2 gene and identification of two regulatory regions required for its pigment cell-specific expression. 792 51

Microphthalmia-associated transcription factor (MITF), the human homolog of the mouse microphthalmia gene product, regulates melanocyte-specific transcription of the tyrosinase gene that codes for an essential enzyme in melanin biosynthesis. In this study, we have cloned and characterized the human genomic DNA segment containing a melanocyte-type exon and its 5'-flanking region of the MITF gene. A major transcriptional initiation site was assigned by primer extension and S1 nuclease mapping analyses using melanoma RNA. Subsequently, the fusion genes, containing the identified 5'-flanking region upstream from the firefly luciferase gene, were constructed and were introduced into pigmented melanoma cells or HeLa cells which do not express MITF mRNA. Transient expression assays show that the 5'-flanking region of 2.3 kb is able to confer preferential expression of a luciferase gene in pigment cells. These results establish that the MITF gene contains a melanocyte-specific promoter.
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PMID:Identification of a melanocyte-type promoter of the microphthalmia-associated transcription factor gene. 864 45