Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

An early gene which augments the expression of the delayed early/late 39K gene of the baculovirus Autographa californica nuclear polyhedrosis virus (AcNPV) was identified by functional mapping. Transient expression of the plasmid p39CAT, containing the bacterial chloramphenicol acetyltransferase coding sequences under the control of the promoter of the 39K protein, was observed in cells cotransfected with AcNPV DNA digested with several restriction endonucleases. However, when p39CAT was cotransfected with viral DNA digested with Bg/II restriction endonuclease, no CAT activity could be detected. To map the location of the Bg/II-sensitive sequences required for efficient expression of 39CAT, p39CAT and Bg/II-digested viral DNA were cotransfected with a PstI library of AcNPV DNA. The PstI-N fragment restored 39CAT activity. A major early 1.3-kb transcript from this fragment was mapped by S1 nuclease analysis. Transient assay experiments indicated that this major transcript of the PstI-N fragment was produced by an immediate early gene, named IE-N. The PstI-N fragment alone did not activate expression of p39CAT but was required when IE-1 was present in limiting quantities.
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PMID:Functional mapping of an AcNPV immediately early gene which augments expression of the IE-1 trans-activated 39K gene. 327 28

LTR units associated with cellular retrovirus-like elements are abundantly present in chromosomal DNA of animal cells. We have analyzed the promoter and enhancer activities of diverse LTR units associated with different members of the murine retrovirus-like family known as VL30. We report here that the structurally heterogenous VL30 LTRs displayed highly variable promoter/enhancer activities. The most active VL30 LTR (designated VL3) promoted CAT activity to levels six-fold higher than the LTR of the strongly transforming retrovirus, MSV. This VL30 transcription unit, containing a unique U3 region, was further characterized by S1 nuclease mapping. VL3 LTR functioned as an enhancer in CAT constructs containing a SV40 promoter. In addition, a defined U3 segment was shown to augment expression of CAT in an orientation independent manner. VL3 LTR also served as an efficient promoter and enhancer in heterologous monkey cells. These results suggest that certain resident LTRs possess promoter and enhancer capacities greater than those possessed by LTRs of infectious retroviruses.
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PMID:Promoter and enhancer activities of long terminal repeats associated with cellular retrovirus-like (VL30) elements. 345 50

We have isolated a DNA segment that contains the presumptive transcriptional and translational control signals located at the 5' end of the mouse alpha 2(I) collagen gene. The DNA sequence of the first exon of this gene and of 400 base pairs preceding the start of transcription was compared with an analogous sequence in the chick alpha 2(I) collagen gene. The most striking similarity is a block of 68 nucleotides surrounding the translation initiation site which is perfectly conserved except for four contiguous nucleotides in the middle of the conserved sequence. These four nonconserved bases lie between the arms of a perfect inverted repeat with nine nucleotides in each arm. The very high degree of sequence conservation of this segment suggests that both the inverted repeat and the rest of the perfectly conserved sequence have a regulatory role, possibly in translation. The segment preceding the transcription start shows blocks of similarities interspersed with dissimilar sequences. The conserved sequences include the TATA box, CAT box, a G/C rich sequence around -110, a segment that contains almost exclusively pyrimidines on one strand and is sensitive to endonuclease S1 in both promoters, and several other segments that extend to 350 base pairs preceding the start of transcription. Although the distances between these regions of similarity and the TATA box are not the same in the two promoters, we believe the conserved sequences play a role in the transcriptional activation of this gene.
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PMID:DNA sequence comparison of the regulatory signals at the 5' end of the mouse and chick alpha 2 type I collagen genes. 620 94

We characterized the transcriptional activity of the long terminal repeat (LTR) of Rous sarcoma virus by constructing a recombinant plasmid, pRSVcat, in which bacterial chloramphenicol acetyltransferase (CAT; acetyl-CoA:chloramphenicol 3-O-acetyltransferase, EC 2.3.1.28) coding sequences are placed under LTR control. We find that the LTR directs relatively high levels of CAT synthesis within 48 hr after calcium phosphate-mediated introduction of this plasmid into CV-1 monkey kidney cells, chicken embryo fibroblasts, Chinese hamster ovary cells, HeLa cells, or mouse NIH/3T3 cells. The level of CAT synthesis is 3-fold higher in CV-1 cells and up to 10-fold higher in HeLa and mouse NIH/3T3 cells than after transfection with a related vector, pSV2cat, carrying CAT sequences under control of the simian virus 40 early promoter. We have shown, by primer extension, that the amounts of CAT-specific mRNAs encoded by pRSVcat and pSV2cat correlate with the levels of CAT enzyme activity. By both S1 nuclease mapping and primer extension, we have demonstrated that the start site for RNA transcription within the LTR of pRSVcat corresponds to previous mapping data. We estimated transfection efficiencies by monitoring immunofluorescence induced by a rhodamine-labeled CAT antibody. Our results indicate that the Rous sarcoma virus LTR can direct synthesis of high levels of functional mRNA and has a wide expression range. The observed high transcriptional activity of the LTR is significant because it has been postulated that this LTR promotes activity of adjacent cellular oncogenes.
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PMID:The Rous sarcoma virus long terminal repeat is a strong promoter when introduced into a variety of eukaryotic cells by DNA-mediated transfection. 629 51

The c-kit proto-oncogene encodes a tyrosine kinase receptor for stem cell factor and plays a critical role in the growth and differentiation of various types of cells including hematopoietic stem cells. To investigate the mechanisms of its transcriptional regulation, we isolated the 5' flanking region of the human c-kit gene and characterized its promoter activity in hematopoietic cells. Nucleotide sequence analysis revealed that the 1.2 kb 5' flanking region lacked a typical "TATA box," but had a relatively high G + C content and four potential Sp1-binding sites. Putative binding sites for AP-2, basic helix-loop-helix proteins, Ets-domain proteins, Myb and GATA-1 were also found. Primer extension and S1 nuclease protection analyses of hematopoietic cells indicated that the major transcription start sites are 62 bp and 58 bp upstream of the translation start site. Essentially the same start sites were detected in non-hematopoietic cells such as small cell lung carcinoma and glioblastoma: this single promoter in c-kit is different from the multiple promoter system of c-fms, a c-kit-related gene, in which at least two promoters are differently used in hematopoietic and non-hematopoietic cells. An analysis of the c-kit 5' flanking region using the bacterial chloramphenicol acetyltransferase gene (CAT assay) in human erythroleukemia HEL cells, which express the endogenous c-kit mRNA at high levels, showed that a region from -180 to -22 is important for the expression of the c-kit gene. In addition, a negative regulatory element(s) is suggested to be involved in the regulation of the c-kit gene expression in mammals.
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PMID:Characterization of the promoter region of the human c-kit proto-oncogene. 750 48

The rat P-450c27/25 (CYP27) gene is expressed as two distinctly sized mRNAs of 2 and 2.3 kb (kilobase). The 2 kb mRNA is the predominant form in the liver with negligible 2.3 kb species. Rat kidney and hepatoma, on the other hand, contain significant levels of the 2.3 kb species. Rat CYP27 gene contains 11 exons of 80-415 nucleotides that are separated by 10 introns of 83 bases to approximately 10 kb. S1 nuclease protection and primer extension analyses using liver RNA showed a prominent 5' terminus 86 nucleotides downstream from the start of exon 2. This site, designated as +1, is the start site for the 2 kb mRNA. 5' RACE analysis of rat kidney and hepatoma RNAs showed the presence of a 5' extended mRNA with a sequence complementary to the Spi2 mRNA. A cryptic TATA box (TTTAAA) is located 24 nucleotides upstream of the 2 kb mRNA transcription initiation site at +1. A 106 bp DNA fragment (sequence -83 to +23) that houses the putative TATA motif forms three differently migrating complexes with nuclear extract from the murine 3T3 cells. DNAse I footprinting and competition with synthetic DNA showed that complex A represents the bound Sp1 factor and complexes B and C are due to unknown factors binding to the -83 to -71 and -20 to -12 sequences, respectively. In vivo transcription analysis using -840/+23 DNA and its 5' deletions cloned in a CAT reporter plasmid suggests that the basal promoter elements are located within sequence -45 to +23 of the gene. Finally, in vitro transcription analysis in HeLa cell nuclear extract showed that intact TTTAAA motif and complex C-forming sequence from this region are essential for transcription initiation at the +1 position of the promoter. Our results demonstrate that the 2 kb mRNA is transcribed as an independent transcript driven by an immediate upstream promoter located within exon 2.
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PMID:Localization of a transcription promoter within the second exon of the cytochrome P-450c27/25 gene for the expression of the major species of two-kilobase mRNA. 757 65

Mouse Hoxb-4 (Hox-2.6) is a homeobox gene that belongs to a family which also includes Hoxa-4, Hoxc-4, and Hoxd-4 and that is related to the Deformed gene in Drosophila melanogaster. We have determined the sequence of 1.2 kb of 5' flanking DNA of mouse Hoxb-4 and by nuclease S1 and primer extension experiments identified two transcription start sites, P1 and P2, 285 and 207 nucleotides upstream of the ATG initiator codon, respectively. We have shown that this region harbors two independent promoters which drive CAT expression in several different cell lines with various efficiencies, suggesting that they are subject to cell-type-specific regulation. Through detailed mutational analysis, we have identified several cis-regulatory elements, located upstream and downstream of the transcription start sites. They include two cell-type-specific negative regulatory elements, which are more active in F9 embryonal carcinoma cells than in neuroblastoma cells (regions a and d at -226 to -186 and +169 to +205, respectively). An additional negative regulatory element has been delimited (region b between +22 and +113). Positive regulation is achieved by binding of HoxTF, a previously unknown factor, to the sequence GCCATTGG (+148 to +155) that is essential for efficient Hoxb-4 expression. We have also defined the minimal promoter sequences and found that they include two 12-bp initiator elements centered around each transcription start site. The complex architecture of the Hoxb-4 promoter provides the framework for fine-tuned transcriptional regulation during embryonic development.
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PMID:Multiple positive and negative regulatory elements in the promoter of the mouse homeobox gene Hoxb-4. 796 51

DNA sequence and transcriptional analyses were performed on the region of the equine herpesvirus type 1 (EHV-1) genome (KyA strain) (map units 0.129 to 0.152) encoding open reading frames (ORFs) 15 and 16. ORF16 encodes a homolog of glycoprotein C of HSV-1 (herpes simplex virus type 1), while ORF15 corresponds in position to HSV-1 UL45 but exhibits no significant homology at the amino acid level. Sequence analyses revealed that the EHV-1 gC ORF of 468 amino acids and ORF15 of 227 amino acids mapped at nucleotides (nt) 716 to 2119 and 2397 to 3077, respectively (relative to the 5' end of the BamHI recognition site at map unit 0.152). ORF15 exhibited significant homology (69% identity) at the amino acid level to the EHV-4 gene located 3' of the EHV-4 gC homolog. Sequence analyses identified potential CAAT and TATA boxes for the EHV-1 gC ORF and a TATA box for ORF15. While no consensus polyadenylation signal was detected between ORFs 15 and 16, two polyadenylation signals were detected 3' of ORF15. Northern blot and S1 nuclease analyses were used to map and characterize the gC and ORF15 mRNAs, and metabolic inhibitors were used to identify the kinetic class of these two genes. The results revealed that gC is a gamma-1 gene which encodes a 2.8-kb mRNA, while ORF15 is a gamma-2 gene encoding a 0.9-kb mRNA which is 3' coterminal with the gC transcript. The gC and ORF15 mRNAs were shown by S1 nuclease analyses to initiate approximately 34 and 26 nucleotides downstream of their respective TATA boxes and to have a common termination site 18 to 20 nucleotides downstream of a consensus polyadenylation signal. Comparative sequence analysis revealed that the KyA strain gC protein differs in only three amino acid residues from the gC protein of the EHV-1 Ab4 and T431 strains, and one of the three amino acid differences occurred within a segment of six contiguous amino acids showing high degree of hydrophilicity in the gC molecule. Further comparative sequence analysis revealed that KyA strain genome has a major deletion in the region of ORF17 which lies 5' of gC in the Ab4 strain. This finding that 1038 base pairs (bp) of the 1203-bp ORF17 is deleted indicates that ORF17 is nonessential for EHV-1 replication in cell culture. To examine the regulation of the EHV-1 gC gene, transient transfection assays using CAT (chloramphenicol acetyltransferase) reporter gene constructs of gC were performed.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:DNA sequence and transcriptional analyses of the region of the equine herpesvirus type 1 Kentucky A strain genome encoding glycoprotein C. 838 60

Overexpression of the Fli-1 gene has been shown to be involved in retrovirus-induced mouse tumors. Cloning of the 5' flanking sequence of the mouse and human Fli-1 exon 1 was performed. At least two major transcription initiation sites were localized respectively at 143 and 114 nucleotides upstream of the previously defined mouse Fli-1 cDNA 5' end. The sequences flanking the CAP sites show good conservation between human and mouse (94%). The promoter region contains a potential TATA box lying 30 bp from one of the major identified CAP sites. Several conserved elements, such as GATA, EBS, GC rich, AP-2, AP-3 elements and a repetition of GA were observed next to the two major CAP sites. Furthermore, this latter was shown to form a H-DNA structure in vitro by S1 nuclease sensitivity experiments. The highly conserved 5' non-translated region of exon 1 is predicted to form a very stable hairpin structure which could regulate the Fli-1 expression at the post-transcriptional level. In Cas-Br-E-induced tumors, all the proviruses are found clustered within 35 nucleotides directly upstream the Fli-1 ATG start codon, thus deleting the hairpin structure from the transcript. Promoter activity was tested using the CAT reporter gene transfected in mouse and human erythroid cell lines. No promoter activity could be detected with various mouse Fli-1 promoter-CAT constructs containing 600 bp of the 5' flanking region, the complete exon 1, the 5' end of intron 1 and/or retroviral LTR sequence. Constructions of the human homologue containing nearly 1.5 kbp of Fli-1 5' flanking region was also inactive in transfected cells. These results suggest that multiple levels of regulation might control the Fli-1 expression.
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PMID:Characterization of the human and mouse Fli-1 promoter regions. 867 8

A single human gene, SIAT1, encodes the beta-galactoside alpha 2,6-sialyltransferase from which multiple mRNA isoforms are generated. In rat, expression of the hepatic mRNA isoform (Form 1) has been defined with respect to the transcriptional initiation site and promoter region. We show here that a similar hepatic SIAT1 mRNA isoform exists in human. Another human mRNA isoform, a mature B-cell-specific mRNA isoform (Form 2), was previously reported. Here, we used 5'-RACE and S1 nuclease protection analysis to define the 5'-untranslated region of Form 2 human SIAT1 mRNA. We demonstrate conclusively that Form 2 mRNA is initiated from a point completely distinct from that of Form 1 mRNA. A number of cis-acting regulatory elements residing immediately 5'of the Form 2 initiation site includes AP-1, AP-2, NF-kappa B, NF-IL6, C/EBP, and CREB. A TATAA box is also present 29 bp 5' of the transcriptional initiation site. CAT reporter gene expression from serially-truncated segments of the 5'-flanking region of the Form 2 initiation site indicates that the segment between -784 and +125 was sufficient to promote high level CAT expression in Louckes, a mature B-cell line. The 5'-flanking region to the human Form 1 initiation site is competent in expression of CAT upon transfection of the fusion construct into HepG2, a human hepatoma cell line. Cellular specificity of expression is apparently retained. Louckes cells expressed CAT efficiently from Form 2 promoter but only marginally from the Form 1 promoter. In contrast, CAT expression from Form 1 promoter is more efficient than from the Form 2 promoter in HepG2 cells.
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PMID:Transcription of the beta-galactoside alpha 2,6-sialyltransferase gene in B lymphocytes is directed by a separate and distinct promoter. 872 35


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