scholarly journals Correlation of gene expression and transformation frequency with the presence of an enhancing sequence in the transforming DNA.

1984 ◽  
Vol 4 (2) ◽  
pp. 368-370 ◽  
Author(s):  
P E Berg ◽  
W F Anderson
Keyword(s):  
Gene Expression ◽  
Dna Sequences ◽  
Base Pair ◽  
Mammalian Cells ◽  
Chinese Hamster ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Transformation Frequency ◽  
Hamster Strain ◽  
Sarcoma Virus

The transformation frequency of cultured mammalian cells is increased 10- to 100-fold when certain DNA sequences are present in the transforming DNA. We wanted to determine whether enhancers, which stimulate gene expression, can cause this phenomenon. Three plasmids, each containing a galactokinase K (galK) gene, were used to transform galK- Chinese hamster cells. One plasmid has no enhancer, another has the simian virus 40 (72-base-pair repeat) enhancer, and the third has the Harvey sarcoma virus (73-base-pair repeat) enhancer. The presence of either enhancer significantly increased the appearance of GalK+ colonies. Galactokinase transient assays in this Chinese hamster strain in the presence of the same plasmids demonstrated an increase in GalK enzyme levels when either enhancer was present. These data indicate that there is a strong correlation between galK expression and transformation frequency that is dependent on the presence of an enhancer in the transforming DNA.

Correlation of gene expression and transformation frequency with the presence of an enhancing sequence in the transforming DNA

1984 ◽  
Vol 4 (2) ◽  
pp. 368-370
Author(s):  
P E Berg ◽  
W F Anderson
Keyword(s):  
Gene Expression ◽  
Dna Sequences ◽  
Base Pair ◽  
Mammalian Cells ◽  
Chinese Hamster ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Transformation Frequency ◽  
Hamster Strain ◽  
Sarcoma Virus

The transformation frequency of cultured mammalian cells is increased 10- to 100-fold when certain DNA sequences are present in the transforming DNA. We wanted to determine whether enhancers, which stimulate gene expression, can cause this phenomenon. Three plasmids, each containing a galactokinase K (galK) gene, were used to transform galK- Chinese hamster cells. One plasmid has no enhancer, another has the simian virus 40 (72-base-pair repeat) enhancer, and the third has the Harvey sarcoma virus (73-base-pair repeat) enhancer. The presence of either enhancer significantly increased the appearance of GalK+ colonies. Galactokinase transient assays in this Chinese hamster strain in the presence of the same plasmids demonstrated an increase in GalK enzyme levels when either enhancer was present. These data indicate that there is a strong correlation between galK expression and transformation frequency that is dependent on the presence of an enhancer in the transforming DNA.

Bovine papilloma virus contains an activator of gene expression at the distal end of the early transcription unit

1983 ◽  
Vol 3 (6) ◽  
pp. 1108-1122
Author(s):  
M Lusky ◽  
L Berg ◽  
H Weiher ◽  
M Botchan
Keyword(s):  
Thymidine Kinase ◽  
Dna Sequences ◽  
Base Pair ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Stable Transformation ◽  
High Molecular Weight Dna ◽  
Papilloma Virus ◽  
Recombinant Plasmids ◽  
Bovine Papilloma Virus

Bovine papilloma virus (BPV) contains a cis-acting DNA element which can enhance transcription of distal promoters. Utilizing both direct and indirect transient transfection assays, we showed that a 59-base-pair DNA sequence from the BPV genome could activate the simian virus 40 promoter from distances exceeding 2.5 kilobases and in an orientation-independent manner. In contrast to the promoter 5'-proximal localization of other known viral activators, this element was located immediately 3' to the early polyadenylation signal in the BPV genome. Deletion of these sequences from the BPV genome inactivated the transforming ability of BPV recombinant plasmids. Orientation-independent reinsertion of this 59-base-pair sequence, or alternatively of activator DNA sequences from simian virus 40 or polyoma virus, restored the transforming activity of the BPV recombinant plasmids. Furthermore, the stable transformation frequency of the herpes simplex virus type 1 thymidine kinase gene was enhanced when linked to restriction fragments of BPV DNA which included the defined activator element. This enhancement was orientation independent with respect to the thymidine kinase promoter. The enhancement also appeared to be unrelated to the establishment of the recombinant plasmids as episomes, since in transformed cells these sequences are found linked to high-molecular-weight DNA. We propose that the enhancement of stable transformation frequencies and the activation of transcription units are in this case alternate manifestations of the same biochemical events.

scholarly journals Simian virus 40 guanine-cytosine-rich sequences function as independent transcriptional control elements in vitro.

1984 ◽  
Vol 4 (12) ◽  
pp. 2911-2920 ◽  
Author(s):  
H Mishoe ◽  
J N Brady ◽  
M Radonovich ◽  
N P Salzman
Keyword(s):  
Rna Polymerase Ii ◽  
Dna Sequences ◽  
Base Pair ◽  
Transcriptional Control ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Control Element ◽  
Late Promoter ◽  
Transcription Control

We have recently shown that DNA sequences located within the simian virus 40 (SV40) G-C-rich, 21-base-pair repeats constitute an important transcriptional control element of the SV40 late promoter (Brady et al., Mol. Cell. Biol. 4:133-141, 1984). To gain further insight into the mechanism by which the SV40 G-C-rich repeats function, we have analyzed the transcriptional properties of several recombinant DNAs. The results presented in this report suggest that the SV40 G-C-rich sequences can function as independent RNA polymerase II transcriptional-control elements. In vitro competition studies demonstrated that sequences within the G-C-rich, 21-base-pair repeats, in the absence of either the SV40 early or late -25 transcriptional-control signals or the major RNA initiation sites, efficiently competed for transcription factors required for SV40 early and late RNA synthesis. Our transcription studies also demonstrated that in the absence of contiguous SV40 transcription control sequences, G-C-rich sequences stimulated initiation of transcription in a bidirectional manner, from proximally located sequences. Finally, we demonstrated that the 21-base-pair-repeat region can stimulate in vitro transcription from the heterologous adenovirus 2 major late promoter.

scholarly journals Bovine papilloma virus contains an activator of gene expression at the distal end of the early transcription unit.

1983 ◽  
Vol 3 (6) ◽  
pp. 1108-1122 ◽  
Author(s):  
M Lusky ◽  
L Berg ◽  
H Weiher ◽  
M Botchan
Keyword(s):  
Thymidine Kinase ◽  
Dna Sequences ◽  
Base Pair ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Stable Transformation ◽  
High Molecular Weight Dna ◽  
Papilloma Virus ◽  
Recombinant Plasmids ◽  
Bovine Papilloma Virus

Bovine papilloma virus (BPV) contains a cis-acting DNA element which can enhance transcription of distal promoters. Utilizing both direct and indirect transient transfection assays, we showed that a 59-base-pair DNA sequence from the BPV genome could activate the simian virus 40 promoter from distances exceeding 2.5 kilobases and in an orientation-independent manner. In contrast to the promoter 5'-proximal localization of other known viral activators, this element was located immediately 3' to the early polyadenylation signal in the BPV genome. Deletion of these sequences from the BPV genome inactivated the transforming ability of BPV recombinant plasmids. Orientation-independent reinsertion of this 59-base-pair sequence, or alternatively of activator DNA sequences from simian virus 40 or polyoma virus, restored the transforming activity of the BPV recombinant plasmids. Furthermore, the stable transformation frequency of the herpes simplex virus type 1 thymidine kinase gene was enhanced when linked to restriction fragments of BPV DNA which included the defined activator element. This enhancement was orientation independent with respect to the thymidine kinase promoter. The enhancement also appeared to be unrelated to the establishment of the recombinant plasmids as episomes, since in transformed cells these sequences are found linked to high-molecular-weight DNA. We propose that the enhancement of stable transformation frequencies and the activation of transcription units are in this case alternate manifestations of the same biochemical events.

scholarly journals Position effects on the timing of replication of chromosomally integrated simian virus 40 molecules in Chinese hamster cells.

1990 ◽  
Vol 10 (8) ◽  
pp. 4345-4355 ◽  
Author(s):  
D M Gilbert ◽  
S N Cohen
Keyword(s):  
Dna Sequences ◽  
Chinese Hamster ◽  
Simian Virus 40 ◽  
Replication Timing ◽  
Simian Virus ◽  
Relative Activity ◽  
T Antigen ◽  
Temperature Sensitive ◽  
Chromosomal Dna ◽  
Position Effects

Simian virus 40 (SV40) DNA molecules chromosomally integrated at different sites in three Chinese hamster lung fibroblast lines replicated during the middle portion of S phase but not precisely at the same time in all three cell lines. The time of replication was unrelated to the presence of T antigen or to its relative activity in promoting SV40 replication. SV40 sequences and chromosomal DNA sequences adjacent to the SV40 insert in one cell line expressing a temperature-sensitive T antigen showed a T-antigen-independent difference in replication timing from the homologous, allelic locus not linked to SV40. Our results indicate that the timing of replication of these integrated SV40 molecules is dependent upon the site of integration and is not determined by the level of T antigen replication-promoting activity.

Chromatin structure of simian virus 40-pBR322 recombinant plasmids in COS-1 cells

1983 ◽  
Vol 3 (12) ◽  
pp. 2203-2210
Author(s):  
J W Innis ◽  
W A Scott
Keyword(s):  
Chromatin Structure ◽  
Plasmid Dna ◽  
Base Pair ◽  
Mammalian Cells ◽  
Simian Virus 40 ◽  
Restriction Enzymes ◽  
Simian Virus ◽  
Dnase I ◽  
Viral Origin ◽  
African Green Monkey Kidney

To study the nucleoprotein structure formed by recombinant plasmid DNA in mammalian cells, nuclei were isolated from COS-1 cells after transfection with a recombinant (pJI1) containing pBR322 sequences and a segment of simian virus 40 containing information for a nuclease-sensitive chromatin structure. The nuclei were incubated with DNase I. DNA fragments which were the size of linear pJI1 DNA were isolated, redigested with restriction enzymes, fractionated by electrophoresis, and detected by hybridization with nick-translated segments prepared from the plasmid DNA. Two DNase I-sensitive sites were detected in the simian virus 40 portion of the plasmid at the same sites that were DNase I sensitive in simian virus 40 chromatin prepared late after infection of African green monkey kidney (BSC-1) cells. One site extended from the viral origin of replication to approximately nucleotide 40. The 21-base pair repeated sequences were relatively DNase I resistant. A second site occurred over the single copy of the 72-base pair segment present in this plasmid. These results indicate that the nuclease-sensitive chromatin structure does not depend on the presence of viral structural proteins. In addition, late viral proteins added to pJI1-transfected COS-1 cells by superinfection with simian virus 40 caused no change in the distribution of DNase I-sensitive sites in plasmid chromatin. Analysis of transfected plasmid DNA may provide a general method applicable to the study of the chromatin structure of cloned segments of DNA.

scholarly journals Rescue of chromosomal T-antigen sequences onto extrachromosomally replicating, defective simian virus 40 DNA by homologous recombination.

1986 ◽  
Vol 6 (4) ◽  
pp. 1320-1325 ◽  
Author(s):  
S Subramani
Keyword(s):  
Homologous Recombination ◽  
Dna Sequences ◽  
Base Pair ◽  
Recombination Event ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Extrachromosomal Dna ◽  
Cos Cells ◽  
Antigen Gene

Recombination between chromosomal and extrachromosomal DNA sequences was analyzed by investigation of the recombinational rescue of a 1,018-base-pair (bp) segment of the T-antigen gene of simian virus 40 from the chromosome of monkey COS cells to two different, extrachromosomally replicating, simian virus 40 DNA molecules lacking this 1,018-bp sequence. The ratio of rescued to unrecombined virus was as high as 10(-3). The rescued molecules, detected optimally 5 to 9 days after transfection of COS cells, had completely recovered the 1,018-bp DNA segment from the chromosome. The recombination event is proposed to occur either by double reciprocal recombination or by gene conversion between the chromosomal T-antigen gene and the extrachromosomal molecules missing the 1,018-bp sequence.

scholarly journals Expression of the mouse dihydrofolate reductase complementary deoxyribonucleic acid in simian virus 40 vectors.

1981 ◽  
Vol 1 (9) ◽  
pp. 854-864 ◽  
Author(s):  
S Subramani ◽  
R Mulligan ◽  
P Berg
Keyword(s):  
Dihydrofolate Reductase ◽  
Chinese Hamster Ovary ◽  
Mammalian Cells ◽  
Deoxyribonucleic Acid ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Ovary Cells ◽  
Complementary Deoxyribonucleic Acid

A mouse complementary deoxyribonucleic acid segment coding for the enzyme dihydrofolate reductase has been cloned in two general classes of vectors containing simian virus 40 deoxyribonucleic acid: (i) those that can be propagated as virions in permissive cells and (ii) those that can be introduced into and maintained stably in various mammalian cells. Both types of vectors express the mouse dihydrofolate reductase by using signals supplied by simian virus 40 deoxyribonucleic acid sequences. Moreover, plasmid vectors carrying the complementary deoxyribonucleic acid segment can complement Chinese hamster ovary cells lacking dihydrofolate reductase.

Simian virus 40 guanine-cytosine-rich sequences function as independent transcriptional control elements in vitro

1984 ◽  
Vol 4 (12) ◽  
pp. 2911-2920
Author(s):  
H Mishoe ◽  
J N Brady ◽  
M Radonovich ◽  
N P Salzman
Keyword(s):  
Rna Polymerase Ii ◽  
Dna Sequences ◽  
Base Pair ◽  
Transcriptional Control ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Control Element ◽  
Late Promoter ◽  
Transcription Control

We have recently shown that DNA sequences located within the simian virus 40 (SV40) G-C-rich, 21-base-pair repeats constitute an important transcriptional control element of the SV40 late promoter (Brady et al., Mol. Cell. Biol. 4:133-141, 1984). To gain further insight into the mechanism by which the SV40 G-C-rich repeats function, we have analyzed the transcriptional properties of several recombinant DNAs. The results presented in this report suggest that the SV40 G-C-rich sequences can function as independent RNA polymerase II transcriptional-control elements. In vitro competition studies demonstrated that sequences within the G-C-rich, 21-base-pair repeats, in the absence of either the SV40 early or late -25 transcriptional-control signals or the major RNA initiation sites, efficiently competed for transcription factors required for SV40 early and late RNA synthesis. Our transcription studies also demonstrated that in the absence of contiguous SV40 transcription control sequences, G-C-rich sequences stimulated initiation of transcription in a bidirectional manner, from proximally located sequences. Finally, we demonstrated that the 21-base-pair-repeat region can stimulate in vitro transcription from the heterologous adenovirus 2 major late promoter.

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