Binding of simian virus 40 large T antigen from virus-infected monkey cells to wild-type and mutant viral replication origins

Tenen, Daniel G.; Taylor, Thomas S.; Haines, Lora L.; Bradley, Margaret K.; Martin, Robert G.; Livingston, David M.

doi:10.1016/s0022-2836(83)80075-8

Cited by 38 publications

(26 citation statements)

References 27 publications

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“…For example, we demonstrated that only two pentanucleotides are required for T-ag double-hexamer formation on the 64-bp core origin (32) and that pentanucleotides 1 and 3 were the preferred substrates for T-ag assembly. Consistent with these observations, dimethyl sulfate studies revealed that T-ag protected pentanucleotides 1 and 3 more than 2 and 4 (6, 31), and preferential binding to the early half of the core origin has been reported by several investigators (55,70,75). Of particular interest, 1,10-phenanthroline-copper ion footprinting studies revealed that on the core origin, T-ag double hexamers and T-ag-obd 131-260 dimers have virtually identical footprints that extend between pentanucleotides 1 and 3 (32).…”

Section: Discussionsupporting

confidence: 79%

The Simian Virus 40 Core Origin Contains Two Separate Sequence Modules That Support T-Antigen Double-Hexamer Assembly

Sreekumar

Prack

Winters

et al. 2000

J Virol

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Using subfragments of the simian virus 40 (SV40) core origin, we demonstrate that two alternative modules exist for the assembly of T-antigen (T-ag) double hexamers. Pentanucleotides 1 and 3 and the early palindrome (EP) constitute one assembly unit, while pentanucleotides 2 and 4 and the AT-rich region constitute a second, relatively weak, assembly unit. Related studies indicate that on the unit made up of pentanucleotide 1 and 3 and the EP assembly unit, the first hexamer forms on pentanucleotide 1 and that owing to additional protein-DNA and protein-protein interactions, the second hexamer is able to form on pentanucleotide 3. Oligomerization on the unit made up of pentanucleotide 2 and 4 and the AT-rich region is initiated by assembly of a hexamer on pentanucleotide 4; subsequent formation of the second hexamer takes place on pentanucleotide 2. Given that oligomerization on the SV40 origin is limited to double-hexamer formation, it is likely that only a single module is used for the initial assembly of T-ag double hexamers. Finally, we discuss the evidence that nucleotide hydrolysis is required for the remodeling events that result in the utilization of the second assembly unit.A thorough understanding of the initiation of DNA replication and its regulation, will require a detailed description of the protein-DNA and protein-protein interactions that take place at origins of replication. Since origins of replication in higher eukaryotic organisms are poorly characterized (8, 21), little is known about the molecular interactions that take place at these sites. Therefore, well-defined viral model systems are being used in an effort to establish the molecular interactions required to initiate DNA replication. One of the best-characterized viral model systems is that based on simian virus 40 (SV40). This virus encodes a single protein, termed T antigen (T-ag) (68), that binds in a site-specific manner to the viral origin of replication, a necessary step for the initiation of DNA replication (72). Several reviews have been published that cover the SV40 origin of replication, T-ag, and the interactions that take place between these molecules (4,7,26). Therefore, only a brief introduction is provided that stresses recent observations in this field.A 64-bp region of the SV40 genome, termed the core origin, is necessary and sufficient for viral replication (19,22,39,52,66). The core origin consists of a central region, termed site II, that is flanked by an AT-rich domain (AT) and a second region, termed the early palindrome (EP) (17). Site II contains four GAGGC pentanucleotides, arranged as inverted pairs, that serve as binding sites for T-ag (20,43,69,71). All three regions of the core origin are required for DNA unwinding and initiation of DNA replication (13,17,32).T-ag is a 708-amino-acid phosphoprotein that contains several structural and functional domains (for reviews, see references 7 and 26). One domain of T-ag, the T-ag origin binding domain (T-ag-obd 131-260 ) has been extensively studied. The purified T-a...

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Section: Discussionsupporting

confidence: 79%

The Simian Virus 40 Core Origin Contains Two Separate Sequence Modules That Support T-Antigen Double-Hexamer Assembly

Sreekumar

Prack

Winters

et al. 2000

J Virol

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“…9. At present these BFDV T antigen-binding sites are less strictly defined than the corresponding binding sites in SV40 (DeLucia et al, 1983;Tegtmeyer et al, 1983;Tenen et al, 1983) or Py Pomerantz et al, 1983;Cowie & Kamen, 1984).…”

Section: Discussionmentioning

confidence: 99%

Expression and DNA binding of budgerigar fledgling disease virus large T antigen

Luo¹,

Müller

Tang

et al. 1994

Journal of General Virology

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Budgerigar fledgling disease virus (BFDV) represents the first non-mammalian member of the polyomavirus genus and possesses uncommon structural and biological properties. Recombinant baculoviruses were constructed to express BFDV small t antigen, large T antigens, as well as a large T deletion mutant T~ and flgalactosidase-T~ fusion proteins to high levels in infected insect cells. A recombinant virus containing a genomic copy of the BFDV early region was used for small t antigen expression, and corresponding introndeleted cDNAs for production of large T antigen derivatives. Recombinant T as well as authentic T antigen proteins from infected chicken embryo fibroblasts were purified using both immunoaffinity and DNA affinity column chromatography. We present evidence that the large T antigen interacts specifically with DNA sequences present in the non-coding region of BFDV; by indirect DNA immunoprecipitation mapping and DNase I footprinting, four regions including 12 DNA-binding sites have been determined that cover most of the BFDV non-coding region. The T antigen binding pattern observed suggests a protein-DNA interaction system considerably different from those of simian virus 40 and other polyomaviruses.

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“…The minimal origin contains several potentially important sequence elements. The 27-bp inverted repeat contains nucleotides essential for binding of T antigen as determined by genetic and biochemical studies (26,35,36,39,61,69). Although there is good evidence that binding of T antigen to this element is required for initiation of DNA replication (43,62,74), the precise biochemical function of T antigen in the initiation process is not known.…”

Section: Downloaded Frommentioning

confidence: 99%

“…ful (16,17,35,69). There are a number of other possible mechanisms that could account for the increased replication efficiency observed in the presence of site I.…”

Section: Downloaded Frommentioning

confidence: 99%

See 1 more Smart Citation

Functional organization of the simian virus 40 origin of DNA replication.

et al. 1986

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Binding of simian virus 40 large T antigen from virus-infected monkey cells to wild-type and mutant viral replication origins

Cited by 38 publications

References 27 publications

The Simian Virus 40 Core Origin Contains Two Separate Sequence Modules That Support T-Antigen Double-Hexamer Assembly

The Simian Virus 40 Core Origin Contains Two Separate Sequence Modules That Support T-Antigen Double-Hexamer Assembly

Expression and DNA binding of budgerigar fledgling disease virus large T antigen

Functional organization of the simian virus 40 origin of DNA replication.

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