scholarly journals Emergence of infectious simian virus 40 whose AT tract in the replication origin/early promoter region is substituted by cellular or viral DNAs

2015 ◽  
Vol 96 (3) ◽  
pp. 601-606 ◽  
Author(s):  
Simon Keiser ◽  
Katharina Schmidt ◽  
Tobias Bethge ◽  
Julia Steiger ◽  
Hans H. Hirsch ◽  
...  
Keyword(s):  
Promoter Region ◽  
Replication Origin ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Early Promoter ◽  
Viral Dnas

Activation of an enhancerless gene by chromosomal integration

1986 ◽  
Vol 6 (12) ◽  
pp. 4179-4184
Author(s):  
H Hamada
Keyword(s):  
Promoter Region ◽  
Genomic Dna ◽  
Simian Virus 40 ◽  
Initiation Site ◽  
Simian Virus ◽  
Chromosomal Integration ◽  
Early Promoter ◽  
Sv40 Enhancer ◽  
Active Expression ◽  
Cat Gene

Expression of enhancerless (E-) and enhancer-containing (E+) genes that are chromosomally integrated was examined. An E- plasmid (pE-cat) containing a chloramphenicol acetyltransferase (cat) gene linked to the simian virus 40 (SV40) early promoter or its E+ counterpart plasmid (pE+-cat) containing the SV40 enhancer was cotransfected into thymidine kinase (TK)-deficient L cells with a cloned tk gene. A number of TK+ transformants were isolated, and expression of the cointegrated cat gene in these cell lines was quantitatively determined by the assay of CAT activity. The results indicated unexpectedly that the E- cat gene was as actively expressed as the E+ cat gene. Analysis of CAT mRNA by primer extension indicated that the E- cat gene, as well as the E+ cat gene, was transcribed from the "native" initiation site contained in the SV40 early promoter region. The active expression of the E- cat gene was maintained in secondary TK+ transformants that arose by transfection with genomic DNA from the primary transformant. These results suggest that expression of the integrated E- cat gene is activated by endogenous enhancer elements.

scholarly journals Activation of an enhancerless gene by chromosomal integration.

1986 ◽  
Vol 6 (12) ◽  
pp. 4179-4184 ◽  
Author(s):  
H Hamada
Keyword(s):  
Promoter Region ◽  
Genomic Dna ◽  
Simian Virus 40 ◽  
Initiation Site ◽  
Simian Virus ◽  
Chromosomal Integration ◽  
Early Promoter ◽  
Sv40 Enhancer ◽  
Active Expression ◽  
Cat Gene

Expression of enhancerless (E-) and enhancer-containing (E+) genes that are chromosomally integrated was examined. An E- plasmid (pE-cat) containing a chloramphenicol acetyltransferase (cat) gene linked to the simian virus 40 (SV40) early promoter or its E+ counterpart plasmid (pE+-cat) containing the SV40 enhancer was cotransfected into thymidine kinase (TK)-deficient L cells with a cloned tk gene. A number of TK+ transformants were isolated, and expression of the cointegrated cat gene in these cell lines was quantitatively determined by the assay of CAT activity. The results indicated unexpectedly that the E- cat gene was as actively expressed as the E+ cat gene. Analysis of CAT mRNA by primer extension indicated that the E- cat gene, as well as the E+ cat gene, was transcribed from the "native" initiation site contained in the SV40 early promoter region. The active expression of the E- cat gene was maintained in secondary TK+ transformants that arose by transfection with genomic DNA from the primary transformant. These results suggest that expression of the integrated E- cat gene is activated by endogenous enhancer elements.

scholarly journals Composite patterns in neutral/neutral two-dimensional gels demonstrate inefficient replication origin usage.

1996 ◽  
Vol 16 (9) ◽  
pp. 4915-4922 ◽  
Author(s):  
R F Kalejta ◽  
J L Hamlin
Keyword(s):  
Replication Origin ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Yeast Cells ◽  
Eukaryotic Cells ◽  
Mapping Technique ◽  
Two Dimensional ◽  
Composite Pattern ◽  
Composite Gel ◽  
Bona Fide

The neutral/neutral two-dimensional (2-D) gel replicon mapping technique has been used to great advantage to localize and characterize origins of replication. Interestingly, many yeast origins display a composite pattern consisting of both a bubble arc and a single-fork arc. Moreover, in every instance in which neutral/neutral 2-D gels have been used to analyze origins in higher eukaryotic cells, two or more adjacent fragments display these composite patterns. We believe that composite patterns signal inefficient origin usage in yeast cells because the replicators in question are not active in every cell cycle and in higher eukaryotic replicons because initiation sites are chosen from among many potential sites lying within a zone. However, others have suggested that the single-fork arcs in these composite gel patterns arise from nicking activity that converts replication bubbles to branched structures that comigrate with bona fide single forks. Here, we have used three different replicon mapping strategies to show that broken simian virus 40 replication bubbles trace unique arcs that are clearly distinguishable from classic, intact single forks. Thus, it is likely that composite 2-D gel patterns represent origins that are inefficiently utilized.

The 5'-flanking region of the mouse thymidylate synthase gene is necessary but not sufficient for normal regulation in growth-stimulated cells

1991 ◽  
Vol 11 (2) ◽  
pp. 1023-1029
Author(s):  
Y Li ◽  
D Li ◽  
K Osborn ◽  
L F Johnson
Keyword(s):  
Thymidylate Synthase ◽  
Cultured Cells ◽  
Transcriptional Start Site ◽  
Simian Virus 40 ◽  
Normal Growth ◽  
Housekeeping Gene ◽  
Simian Virus ◽  
Coding Region ◽  
Proliferating Cells ◽  
Early Promoter

The thymidylate synthase (TS) gene is a housekeeping gene that is expressed at much higher levels in proliferating cells than in quiescent cells. We have studied the role of the TS 5'-flanking sequences in regulating the level of expression of the mouse TS gene. A variety of chimeric TS minigenes that contain different promoters linked either to the TS coding region (with or without introns) or to the chloramphenicol acetyltransferase (CAT) coding region were constructed. The activities of the minigenes were determined by transfecting them into cultured cells and measuring the levels of mRNA or enzyme derived from the chimeric genes. We found that the mouse TS promoter had about the same strength as the simian virus 40 early promoter but was significantly stronger than the herpes simplex virus thymidine kinase promoter. Stable transfection studies revealed that minigenes consisting of the normal TS promoter (extending to -1 kb), coding region, and polyadenylation signal were regulated normally in response to growth stimulation. When the TS promoter was replaced by the simian virus 40 early promoter or by a TS promoter that retained only 60 nucleotides upstream of the first transcriptional start site, the minigene was expressed constitutively. A minigene consisting of the TS promoter (extending to -1 kb) linked to the CAT coding region was also expressed constitutively. These observations indicate that sequences upstream of the transcriptional start sites of the TS gene are necessary, although not sufficient, for normal growth-regulated expression of the mouse TS gene.

SR alpha promoter: an efficient and versatile mammalian cDNA expression system composed of the simian virus 40 early promoter and the R-U5 segment of human T-cell leukemia virus type 1 long terminal repeat

1988 ◽  
Vol 8 (1) ◽  
pp. 466-472 ◽  
Author(s):  
Y Takebe ◽  
M Seiki ◽  
J Fujisawa ◽  
P Hoy ◽  
K Yokota ◽  
...  
Keyword(s):  
Leukemia Virus ◽  
Expression System ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Cell Leukemia ◽  
Cell Leukemia Virus Type ◽  
Early Promoter ◽  
Human T Cell ◽  
T Cell Leukemia Virus

We developed a novel promoter system, designated SR alpha, which is composed of the simian virus 40 (SV40) early promoter and the R segment and part of the U5 sequence (R-U5') of the long terminal repeat of human T-cell leukemia virus type 1. The R-U5' sequence stimulated chloramphenicol acetyltransferase (CAT) gene expression only when placed immediately downstream of the SV40 early promoter in the sense orientation. The SR alpha expression system was 1 or 2 orders of magnitude more active than the SV40 early promoter in a wide variety of cell types, including fibroblasts and lymphoid cells, and was capable of promoting a high level of expression of various lymphokine cDNAs. These features of the SR alpha promoter were incorporated into the pcD-cDNA expression cloning vector originally developed by Okayama and Berg.

scholarly journals Recombinant genomes which express chloramphenicol acetyltransferase in mammalian cells.

1982 ◽  
Vol 2 (9) ◽  
pp. 1044-1051 ◽  
Author(s):  
C M Gorman ◽  
L F Moffat ◽  
B H Howard
Keyword(s):  
Promoter Region ◽  
Mammalian Cells ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Chloramphenicol Acetyltransferase ◽  
Repeat Sequence ◽  
Monkey Kidney ◽  
Sv40 Promoter ◽  
Hindiii Site ◽  
African Green Monkey Kidney

We constructed a series of recombinant genomes which directed expression of the enzyme chloramphenicol acetyltransferase (CAT) in mammalian cells. The prototype recombinant in this series, pSV2-cat, consisted of the beta-lactamase gene and origin of replication from pBR322 coupled to a simian virus 40 (SV40) early transcription region into which CAT coding sequences were inserted. Readily measured levels of CAT accumulated within 48 h after the introduction of pSV2-cat DNA into African green monkey kidney CV-1 cells. Because endogenous CAT activity is not present in CV-1 or other mammalian cells, and because rapid, sensitive assays for CAT activity are available, these recombinants provided a uniquely convenient system for monitoring the expression of foreign DNAs in tissue culture cells. To demonstrate the usefulness of this system, we constructed derivatives of pSV2-cat from which part or all of the SV40 promoter region was removed. Deletion of one copy of the 72-base-pair repeat sequence in the SV40 promoter caused no significant decrease in CAT synthesis in monkey kidney CV-1 cells; however, an additional deletion of 50 base pairs from the second copy of the repeats reduced CAT synthesis to 11% of its level in the wild type. We also constructed a recombinant, pSV0-cat, in which the entire SV40 promoter region was removed and a unique HindIII site was substituted for the insertion of other promoter sequences.

Activity of simian virus 40 early promoter in rabbit embryos

1994 ◽  
Vol 41 (1) ◽  
pp. 281 ◽  
Author(s):  
B. Ramos ◽  
R. de Armas ◽  
J. de la Fuente ◽  
F.O. Castro
Keyword(s):  
Simian Virus 40 ◽  
Simian Virus ◽  
Early Promoter ◽  
Rabbit Embryos

scholarly journals A putative origin of replication of plasmids derived from Epstein-Barr virus is composed of two cis-acting components.

1985 ◽  
Vol 5 (8) ◽  
pp. 1822-1832 ◽  
Author(s):  
D Reisman ◽  
J Yates ◽  
B Sugden
Keyword(s):  
Dna Sequences ◽  
Epstein Barr Virus ◽  
Simian Virus 40 ◽  
Repeated Sequence ◽  
Simian Virus ◽  
Nuclear Antigen ◽  
Barr Virus ◽  
Early Promoter ◽  
The Family ◽  
Epstein Barr

A genetic element of Epstein-Barr virus, oriP, when present on recombinant plasmids allows those plasmids to replicate and to be maintained in cells that express the Epstein-Barr virus-encoded nuclear antigen EBNA-1. Here we define the DNA sequences required for oriP activity. Two noncontiguous regions of oriP are required in cis for activity. One consists of approximately 20 tandem, imperfect copies of a 30-base-pair (bp) sequence. The other required region, approximately 1,000 bp away, is at most 114 bp in length and contains a 65-bp region of dyad symmetry. When present together on a plasmid, these two components supported plasmid replication even when the distance between them was varied or their relative orientation was altered, or both. When present alone on a plasmid that expresses a selectable marker, the family of 30-bp repeats efficiently conferred a transient drug-resistant phenotype in human 143 cells that is dependent on the presence of EBNA-1. This result leads us to suggest that EBNA-1 interacts with the 30-bp repeated sequence to activate oriP. To test whether the 30-bp repeats might cause the increased transient expression of drug resistance by enhancing transcription, the family of 30-bp repeats was tested for the ability to activate the simian virus 40 early promoter present in plasmid pA10CAT2 (Laimins, et al., Proc. Natl. Acad. Sci. U.S.A. 79:6453-6457). In this assay, the 30-bp repeats could activate the simian virus 40 early promoter in Raji cells, an EBNA-positive Burkitt's lymphoma cell line, but not detectably an EBNA-positive 143 cells in which oriP also functions.

scholarly journals An enhancer with cell-type dependent activity is located between the myeloid and epithelial aminopeptidase N (CD 13) promoters

1997 ◽  
Vol 322 (3) ◽  
pp. 899-908 ◽  
Author(s):  
Jørgen OLSEN ◽  
Klaus KOKHOLM ◽  
Jesper T. TROELSEN ◽  
Liselotte LAUSTSEN
Keyword(s):  
Transcriptional Start Site ◽  
Simian Virus 40 ◽  
K562 Cells ◽  
Simian Virus ◽  
Aminopeptidase N ◽  
Cell Type ◽  
Independent Manner ◽  
Specific Expression ◽  
Enhancer Activity ◽  
Early Promoter

The 5´ flanking region of the gene encoding the small intestinal brush-border peptidase aminopeptidase N (APN) was screened for the presence of enhancer regions. A 300 bp region with enhancer activity was identified 2.7 kb upstream of the transcriptional start site which is used in epithelial cells. The enhancer stimulated transcription from a heterologous promoter (the simian virus 40 early promoter) in a position- and orientation-independent manner. The activity of the enhancer is cell-type dependent and it is active in liver (HepG2), intestinal (Caco-2) and myeloid (K562) cells. As the epithelial APN promoter is active in the first two cell-types and the myeloid APN promoter in the last, the results may suggest that the enhancer, through a cooperation with either of the promoters, is important for the tissue-specific expression of APN. A detailed analysis of the enhancer led to the identification of four functionally important regions that are protected against DNase I digestion by Caco-2 nuclear extract. Sequence analysis suggests that two of the regions may interact with members of the Ets transcription factor family (Ets is a transformation-specific protein first discovered in the E26 avian erythroblastosis virus), one region with a CCAAT enhancer-binding protein and one region with Sp1, a transcriptional activator first described as a factor binding to the simian virus 40 early promoter.

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