T-antigen is the only detectable protein on the nucleosome-free origin region of isolated simian virus 40 minichromosomes

Chromosoma ◽  
1985 ◽  
Vol 92 (5) ◽  
pp. 391-400 ◽  
Author(s):  
Etienne Weiss ◽  
Dipankar Ghose ◽  
Patrick Schultz ◽  
Pierre Oudet
Keyword(s):  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Origin Region

Carcinogen-induced DNA amplification in vitro: overreplication of the simian virus 40 origin region in extracts from carcinogen-treated CO60 cells

1990 ◽  
Vol 10 (1) ◽  
pp. 75-83
Author(s):  
Y Berko-Flint ◽  
S Karby ◽  
D Hassin ◽  
S Lavi
Keyword(s):  
De Novo ◽  
Chinese Hamster ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Dna Molecules ◽  
Viral Origin ◽  
Cell Extracts ◽  
Origin Region

An in vitro system to study carcinogen-induced amplification in simian virus 40 (SV40)-transformed Chinese hamster (CO60) cells is described. SV40 amplification in this system resembled in many aspects the viral overreplication observed in drug-treated CO60 cells. Cytosolic extracts from N-methyl-N'-nitro-N-nitrosoguanidine-treated cells supported de novo DNA synthesis in the presence of excess exogenous T antigen and the SV40-containing plasmid pSVK1. The pattern of viral replication in these extracts was unique, since only the 2.4-kilobase-pair region spanning the origin was overreplicated, whereas distal sequences were not replicated significantly. Extracts from control cells supported only marginal levels of replication. In HeLa extracts, complete SV40 DNA molecules were replicated efficiently. The overreplication of the origin region in CO60 cell extracts was bidirectional and symmetrical. A fraction of the newly synthesized DNA molecules underwent a second round of replication, yielding MboI-sensitive fragments representing the 2.4-kilobase-pair region around the origin. The mechanisms controlling the amplification of the viral origin region, the nature of the cellular factors induced in the carcinogen-treated cells, and their putative association with general drug-induced SOS-like responses are discussed.

scholarly journals Sequence-specific binding of simian virus 40 A protein to nonorigin and cellular DNA.

1984 ◽  
Vol 4 (12) ◽  
pp. 2631-2638 ◽  
Author(s):  
P J Wright ◽  
A L DeLucia ◽  
P Tegtmeyer
Keyword(s):  
Specific Binding ◽  
Consensus Sequence ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Binding Affinities ◽  
Sequence Variations ◽  
Origin Region ◽  
Cellular Dna ◽  
Many Sources

The simian virus 40 A protein (T antigen) recognized and bound to the consensus sequence 5'-GAGGC-3' in DNA from many sources. Sequence-specific binding to single pentanucleotides in randomly chosen DNA predominated over binding to nonspecific sequences. The asymmetric orientation of protein bound to nonorigin recognition sequences also resembled that of protein bound to the origin region of simian virus 40 DNA. Sequence variations in the DNA adjacent to single pentanucleotides influenced binding affinities even though methylation interference and protection studies did not reveal specific interactions outside of pentanucleotides. Thus, potential locations of A protein bound to any DNA can be predicted although the determinants of binding affinity are not yet understood. Sequence-specific binding of A protein to cellular DNA would provide a mechanism for specific alterations of host gene expression that facilitate viral function.

scholarly journals Primer-DNA formation during simian virus 40 DNA replication in vitro.

1993 ◽  
Vol 13 (5) ◽  
pp. 2882-2890 ◽  
Author(s):  
D Denis ◽  
P A Bullock
Keyword(s):  
Dna Replication ◽  
Proliferating Cell Nuclear Antigen ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Nuclear Antigen ◽  
Origin Region ◽  
Sv40 Dna ◽  
Proliferating Cell

Studies of simian virus 40 (SV40) DNA replication in vitro have identified a small (approximately 30-nucleotide) RNA-DNA hybrid species termed primer-DNA. Initial experiments indicated that T antigen and the polymerase alpha-primase complex are required to form primer-DNA. Proliferating cell nuclear antigen, and presumably proliferating cell nuclear antigen-dependent polymerases, is not needed to form this species. Herein, we present an investigation of the stages at which primer-DNA functions during SV40 DNA replication in vitro. Hybridization studies indicate that primer-DNA is initially formed in the origin region and is subsequently synthesized in regions distal to the origin. At all time points, primer-DNA is synthesized from templates for lagging-strand DNA replication. These studies indicate that primer-DNA functions during both initiation and elongation stages of SV40 DNA synthesis. Results of additional experiments suggesting a precursor-product relationship between formation of primer-DNA and Okazaki fragments are presented.

Sequence-specific binding of simian virus 40 A protein to nonorigin and cellular DNA

1984 ◽  
Vol 4 (12) ◽  
pp. 2631-2638 ◽  
Author(s):  
P J Wright ◽  
A L DeLucia ◽  
P Tegtmeyer
Keyword(s):  
Specific Binding ◽  
Consensus Sequence ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Binding Affinities ◽  
Sequence Variations ◽  
Origin Region ◽  
Cellular Dna ◽  
Many Sources

The simian virus 40 A protein (T antigen) recognized and bound to the consensus sequence 5'-GAGGC-3' in DNA from many sources. Sequence-specific binding to single pentanucleotides in randomly chosen DNA predominated over binding to nonspecific sequences. The asymmetric orientation of protein bound to nonorigin recognition sequences also resembled that of protein bound to the origin region of simian virus 40 DNA. Sequence variations in the DNA adjacent to single pentanucleotides influenced binding affinities even though methylation interference and protection studies did not reveal specific interactions outside of pentanucleotides. Thus, potential locations of A protein bound to any DNA can be predicted although the determinants of binding affinity are not yet understood. Sequence-specific binding of A protein to cellular DNA would provide a mechanism for specific alterations of host gene expression that facilitate viral function.

scholarly journals Carcinogen-induced DNA amplification in vitro: overreplication of the simian virus 40 origin region in extracts from carcinogen-treated CO60 cells.

1990 ◽  
Vol 10 (1) ◽  
pp. 75-83 ◽  
Author(s):  
Y Berko-Flint ◽  
S Karby ◽  
D Hassin ◽  
S Lavi
Keyword(s):  
De Novo ◽  
Chinese Hamster ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Dna Molecules ◽  
Viral Origin ◽  
Cell Extracts ◽  
Origin Region

An in vitro system to study carcinogen-induced amplification in simian virus 40 (SV40)-transformed Chinese hamster (CO60) cells is described. SV40 amplification in this system resembled in many aspects the viral overreplication observed in drug-treated CO60 cells. Cytosolic extracts from N-methyl-N'-nitro-N-nitrosoguanidine-treated cells supported de novo DNA synthesis in the presence of excess exogenous T antigen and the SV40-containing plasmid pSVK1. The pattern of viral replication in these extracts was unique, since only the 2.4-kilobase-pair region spanning the origin was overreplicated, whereas distal sequences were not replicated significantly. Extracts from control cells supported only marginal levels of replication. In HeLa extracts, complete SV40 DNA molecules were replicated efficiently. The overreplication of the origin region in CO60 cell extracts was bidirectional and symmetrical. A fraction of the newly synthesized DNA molecules underwent a second round of replication, yielding MboI-sensitive fragments representing the 2.4-kilobase-pair region around the origin. The mechanisms controlling the amplification of the viral origin region, the nature of the cellular factors induced in the carcinogen-treated cells, and their putative association with general drug-induced SOS-like responses are discussed.

Primer-DNA formation during simian virus 40 DNA replication in vitro

1993 ◽  
Vol 13 (5) ◽  
pp. 2882-2890
Author(s):  
D Denis ◽  
P A Bullock
Keyword(s):  
Dna Replication ◽  
Proliferating Cell Nuclear Antigen ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Nuclear Antigen ◽  
Origin Region ◽  
Sv40 Dna ◽  
Proliferating Cell

Studies of simian virus 40 (SV40) DNA replication in vitro have identified a small (approximately 30-nucleotide) RNA-DNA hybrid species termed primer-DNA. Initial experiments indicated that T antigen and the polymerase alpha-primase complex are required to form primer-DNA. Proliferating cell nuclear antigen, and presumably proliferating cell nuclear antigen-dependent polymerases, is not needed to form this species. Herein, we present an investigation of the stages at which primer-DNA functions during SV40 DNA replication in vitro. Hybridization studies indicate that primer-DNA is initially formed in the origin region and is subsequently synthesized in regions distal to the origin. At all time points, primer-DNA is synthesized from templates for lagging-strand DNA replication. These studies indicate that primer-DNA functions during both initiation and elongation stages of SV40 DNA synthesis. Results of additional experiments suggesting a precursor-product relationship between formation of primer-DNA and Okazaki fragments are presented.

Sign in / Sign up

Export Citation Format

Share Document