Cellular Transcription Factor Sp1 Recruits Simian Virus 40 Capsid Proteins to the Viral Packaging Signal,
            <i>ses</i>

Gordon‐Shaag, Ariela; Ben-nun-Shaul, Orly; Roitman, Vered; Yosef, Yael; Oppenheim, Ariella

doi:10.1128/jvi.76.12.5915-5924.2002

Cited by 40 publications

(41 citation statements)

References 38 publications

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“…Sp1, a ubiquitous transcription factor, participates in simian virus 40 (SV-40) assembly. It is thought that the VP1-VP2/3 (major capsid protein complex of SV-40) is recruited to ses, the cis-acting packaging signal, by Sp1 (14,32). According Gel mobility shift assays were performed using fraction 22 ( Fig.…”

Section: Discussionmentioning

confidence: 99%

Binding of CCAAT Displacement Protein CDP to Adenovirus Packaging Sequences

Erturk

Ostapchuk

Wells

et al. 2003

J Virol

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Adenovirus (Ad) type 5 DNA packaging is initiated in a polar fashion from the left end of the genome. The packaging process is dependent upon the cis-acting packaging domain located between nucleotides 194 and 380. Seven A/T-rich repeats have been identified within this domain that direct packaging. A1, A2, A5, and A6 are the most important repeats functionally and share a bipartite sequence motif. Several lines of evidence suggest that there is a limiting trans-acting factor(s) that plays a role in packaging. Two cellular activities that bind to minimal packaging domains in vitro have been previously identified. These binding activities are P complex, an uncharacterized protein(s), and chicken ovalbumin upstream promoter transcription factor (COUP-TF). In this work, we report that a third cellular protein, octamer-1 protein (Oct-1), binds to minimal packaging domains. In vitro binding analyses and in vivo packaging assays were used to examine the relevance of these DNA binding activities to Ad DNA packaging. The results of these experiments reveal that COUP-TF and Oct-1 binding does not play a functional role in Ad packaging, whereas P-complex binding directly correlates with packaging function. We demonstrate that P complex contains the cellular protein CCAAT displacement protein (CDP) and that full-length CDP is found in purified virus particles. In addition to cellular factors, previous evidence indicates that viral factors play a role in the initiation of viral DNA packaging. We propose that CDP, in conjunction with one or more viral proteins, binds to the packaging sequences of Ad to initiate the encapsidation process.The assembly of adenovirus (Ad) particles has been studied using a large number of viral temperature-sensitive mutants, blocked at different stages of assembly at the restrictive temperature, and by pulse-chase kinetic analyses (7,8,10). The results from these studies suggest that Ad DNA is inserted into preformed empty capsids late in the viral life cycle. Whether the viral genome enters the prohead in association with viral core proteins, or as a separate entity, is unclear. The exact structure of the viral DNA before and during entry also is not known. Ad DNA packaging occurs in a polar fashion from the left end of the genome. Polarity of adenoviral DNA packaging was initially demonstrated by the finding that left end sequences were overrepresented within incomplete viral particles containing DNA of subgenomic length (6, 43). The left ends of Ad type 3 (Ad3), Ad5, and Ad16, representatives of Ad subgroups B and C, harbor conserved packaging signals (15,19,33,36). These conserved cis-acting packaging domains suggest a similar mechanism of selective and polar DNA packaging for all Ad subgroups.Ad5 DNA encapsidation is dependent on cis-acting sequences located on the left end of the genome between nucleotides (nt) 194 and 380 (15, 16, 22, 39). The left end of the Ad5 genome is depicted in Fig. 1A. Through deletion and linker scanning mutagenesis, seven repeats have been identified within this...

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Section: Discussionmentioning

confidence: 99%

Binding of CCAAT Displacement Protein CDP to Adenovirus Packaging Sequences

Erturk

Ostapchuk

Wells

et al. 2003

J Virol

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“…Glutathione transferase (GST)-VP3, GST-VP3C35, and GST-VP3C49, expressed from pGEX-VP3 (14), pGEX-VP3C35, and pGEX-VP3C49 (15), were purified on glutathione (GSH)-agarose resin as recommended by the manufacturer with minor variations as previously described (15). GST-VP3⌬C13 was expressed from pGEX-VP3⌬C13 (5), kindly provided by Harumi Kasamatsu.…”

Section: Methodsmentioning

confidence: 99%

“…Late in the infection cycle, SV40 usurps cellular transcription factor Sp1 for the recruitment of the capsid proteins to the viral packaging signal, ses, conferring specific DNA recognition upon the proteins, which otherwise bind to DNA nonspecifically. Thus, the capsid building blocks overcome the problem of recognizing the SV40 minichromosome in the presence of excess cellular chromatin within the nucleus (14,15). In this study we discovered a second host factor, the nuclear enzyme poly(ADP-ribose) polymerase (PARP), that participates at late stages of the SV40 life cycle.…”

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confidence: 95%

“…The Sp1 interactive domain of VP2/3 is also present at the carboxy terminus, overlapping the DNA-binding domain (14). It was proposed that the recruitment complex forms a nucleation center at ses (15) and that the first step in capsid assembly is the formation of a fivefold symmetric complex with a "pentavalent" pentamer at its center (35). Assembly is thought to occur by gradual addition and organization of capsid building blocks around the SV40 chromatin (2,13).…”

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confidence: 99%

“…A single molecule of VP2 or VP3 is firmly anchored in the inner cavity of each VP1 pentamer (VP1 5 ) by hydrophobic interactions (3,15), through a region near, but not at, the carboxy terminus of VP2/3 (see Fig. 3).…”

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The Abundant Nuclear Enzyme PARP Participates in the Life Cycle of Simian Virus 40 and Is Stimulated by Minor Capsid Protein VP3

Gordon‐Shaag

Yosef

El-Latif

et al. 2003

J Virol

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The abundant nuclear enzyme poly(ADP-ribose) polymerase (PARP) functions in DNA damage surveillance and repair and at the decision between apoptosis and necrosis. Here we show that PARP binds to simian virus 40 (SV40) capsid proteins VP1 and VP3. Furthermore, its enzymatic activity is stimulated by VP3 but not by VP1. Experiments with purified mutant proteins demonstrated that the PARP binding domain in VP3 is localized to the 35 carboxy-terminal amino acids, while a larger peptide of 49 amino acids was required for full stimulation of its activity. The addition of 3-aminobenzamide (3-AB), a known competitive inhibitor of PARP, demonstrated that PARP participates in the SV40 life cycle. The titer of SV40 propagated on CV-1 cells was reduced by 3-AB in a dose-dependent manner. Additional experiments showed that 3-AB did not affect viral DNA replication or capsid protein production. PARP did not modify the viral capsid proteins in in vitro poly(ADP-ribosylation) assays, implying that it does not affect SV40 infectivity. On the other hand, it greatly reduced the magnitude of the host cytopathic effects, a hallmark of SV40 infection. Additional experiments suggested that the stimulation of PARP activity by VP3 leads the infected cell to a necrotic pathway, characterized by the loss of membrane integrity, thus facilitating the release of mature SV40 virions from the cells. Our studies identified a novel function of the minor capsid protein VP3 in the recruitment of PARP for the SV40 lytic process.Simian virus 40 (SV40) is a papovavirus, with a small, double-stranded, circular DNA genome of 5.2 kb (37a). The viral capsid, surrounding the viral minichromosome, is composed of three virus-encoded proteins, VP1, VP2, and VP3. Seventy-two pentamers of VP1 form the outer shell, while VP2 and VP3 bridge between the VP1 shell and the chromatin core. VP3 translation initiates from an internal AUG within the VP2 coding sequence, utilizing the same translational frame. Thus, except for the amino part that is unique to VP2, the two proteins are identical and are commonly referred to as VP2/3. The VP1 monomer is composed of an antiparallel ␤-strand core with a jelly roll topology, with a short N-terminal arm that contains the DNA-binding domain and nuclear localization signal (21) and a long C-terminal arm (22). VP1 monomers are tightly bound in pentamers, forming structures of fivefold symmetry with an inward-facing cavity (22, 35). The VP1 pentamers are tied together in the capsid through their carboxy-terminal arms. The five arms extending from each pentamer are inserted into the neighboring pentamers in three distinct kinds of interactions. This unique type of bonding underlies the variability in contacts between the identical building blocks, allowing the flexibility required for the packing geometry (22).A single molecule of VP2 or VP3 is firmly anchored in the inner cavity of each VP1 pentamer (VP1 5 ) by hydrophobic interactions (3, 15), through a region near, but not at, the carboxy terminus of VP2/3 (see Fig. 3). The ami...

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Transcriptional regulation of human eosinophil RNase2 by the liver‐enriched hepatocyte nuclear factor 4

Wang¹,

Ho²,

Lan³

et al. 2008

J of Cellular Biochemistry

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Human eosinophil-derived neurotoxin (EDN, RNase2) and eosinophil cationic protein (ECP, RNase3) sequences possess as high as 92% identity in their promoter regions. The major difference within this region is a 34-nucleotide (34-nt) segment appeared only in the edn promoter. In addition, six discrete segments existed in the regulatory regions of both edn and ecp. Our previous study indicated that the 34-nt segment is responsive for higher transcription activity of edn in comparison with ecp, via binding to transcription activator Sp1. In this study, the roles of the six discrete segments in transcription regulation were investigated and the -350/-329 region (ednR2) was shown to be involved in the regulation of edn expression. When the ednR2 segment of edn was replaced with that of ecp, a significant decrease in edn promoter activity was detected. Supershift, chromatin immunoprecipitation, and DNA affinity precipitation assays further showed that a transcription factor HNF4 bound to the ednR2 region of edn promoter in vitro. Interestingly, HNF4 overexpression resulted in the reduction of edn promoter activity in HepG2 cells, due to involvement of both ednR2 and the 34-nt regions, and direct interaction between HNF4 and Sp1, which abolishes Sp1 binging to the 34-nt segment. Moreover, when the Sp1 was depleted in the cell, overexpressed HNF4 enhanced edn promoter activity. Our results provide novel mechanisms for HNF4 function as an activator to regulate edn promoter activity, which account for differential transcription regulation of human eosinophil RNases.

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Cellular Transcription Factor Sp1 Recruits Simian Virus 40 Capsid Proteins to the Viral Packaging Signal, ses

Cited by 40 publications

References 38 publications

Binding of CCAAT Displacement Protein CDP to Adenovirus Packaging Sequences

Binding of CCAAT Displacement Protein CDP to Adenovirus Packaging Sequences

The Abundant Nuclear Enzyme PARP Participates in the Life Cycle of Simian Virus 40 and Is Stimulated by Minor Capsid Protein VP3

Transcriptional regulation of human eosinophil RNase2 by the liver‐enriched hepatocyte nuclear factor 4

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