Activation of BPV-1 replication in vitro by the transcription factor E2

Yang, Liu; Li, Rong; Mohr, Ian; Clark, Robin; Botchan, Michael R.

doi:10.1038/353628a0

Cited by 275 publications

(416 citation statements)

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“…Fax +4471 247 6509. e-mail a.storey@lhmc.ac.uk been limited by the lack of an in vitro method of virus propagation and the production of viral particles. Transient assays have proved useful, however, enabling the viral origin to be mapped, first for bovine papillomavirus type 1 (BPV-1) and then more recently for other HPVs (Yang et al, 1991;Chiang et al, 1992a;Del Vecchio et al, 1992;Sverdrup & Kahn, 1994). These studies have also demonstrated that viral replication has an absolute requirement for two virally encoded proteins, E1 and E2 (Ustav & Stenlund, 1991;Yang et al, 1991;Chiang et al, 1992b).…”

Section: Introductionmentioning

confidence: 99%

“…The BPV-1 E1 protein is a phosphoprotein of about 68 kDa which binds ATP (Blitz & Laimins, 1991;Sun et al, 1990) and possesses an intrinsic ATPase and helicase activity (Seo et al, 1993). The BPV-1 E1 protein contains a consensus nucleotide binding sequence in the Cterminal region of the protein, and binds to specific sequences in the viral origin of replication (orO located in the URR (Wilson & Ludes-Meyers, 1991;Yang et al, 1991). Formation of the complex between BPV-1 E1 and E2 can be modulated by phosphorylation of the E2 protein, and mutations within the C terminus of the E1 protein abolish the binding of E2 (Lusky & Fontaine, 1991).…”

Section: Introductionmentioning

confidence: 99%

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Mutations in the human papillomavirus type 16 E2 protein identify a region of the protein involved in binding to E1 protein

Storey

Piccini

Massimi

et al. 1995

Journal of General Virology

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Papillomavirus DNA replication is primarily dependent upon two viral gene products, E1 and E2. Work with bovine papillomavirus has shown that the E2 protein can bind directly to the E1 protein and enhance the binding of E1 to the viral origin of replication. However, little is known about the mechanism of interaction between E1 and E2 proteins. In this study we have analysed in detail the association between human papillomavirus type 16 (HPV-16) E1 and E2 proteins. Using a purified glutathione S-transferase-HPV-16 E1 fusion protein from Escherichia coli and E2 proteins produced by in vitro transcription-translation, we have developed a rapid and simple method for investigating the association between E1 and E2 in vitro. The binding of E2 to E1 was found to be dependent on sequences in the Nterminal activation domain of the E2 protein. Truncated forms of E2, including a putative repressor form of E2 encoding the DNA binding domain, failed to associate with E1 in this assay. The region of E2 required for efficient binding to E1 was then localized using mutants in the activation domain of E2. These results demonstrated that only a short region of E2 was required for association with El. This region of E2 was found to be highly conserved amongst all papillomaviruses, suggesting a conservation of E2 function and a common mechanism of interaction between these virally encoded proteins.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Mutations in the human papillomavirus type 16 E2 protein identify a region of the protein involved in binding to E1 protein

Storey

Piccini

Massimi

et al. 1995

Journal of General Virology

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“…Replication of BPV-1 DNA in cultured cells or in cell-free systems depends on two virusencoded proteins, the full-length products of the El and E2 open reading frames (ORFs) (8,9). The minimal BPV-1 ori sequence is located at the 3' end of the upstream regulatory region (URR) within a 60-base-pair (bp) DNA fragment including an (A + T)-rich region, a consensus sequence to which all papillomaviral E2 proteins bind, and an El protein binding site spanning nucleotide (nt) 1 (9, 10).…”

mentioning

confidence: 99%

Viral E1 and E2 proteins support replication of homologous and heterologous papillomaviral origins.

Chiang

Ustav

Stenlund

et al. 1992

Proc. Natl. Acad. Sci. U.S.A.

281

269

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We have shown that El and E2 proteins of human papillomavirus type 11 (HPV-11) were essential to support the replication of the homologous viral origin (on) in a transient replication assay, similar to reports on bovine papillomavirus type 1 (BPV-1). Unexpectedly, matched or even mixed combinations of El and E2 proteins from HPV-11 or BPV-l replicated either on in human, monkey, and rodent cell lines of epithelial or fibroblastic lineage, albeit with varied efficiencies. Either set of viral proteins was also able to initiate replication of ori-containing plasmids from many other human and animal papillomaviruses. Thus the interactions among the cis elements and trans factors of papillomaviruses are more conserved than expected from the other members of the papovavirus family, simian virus 40 and polyomavirus, for which large tumor antigen does not replicate a heterologous on in either permissive or nonpermissive cells. We infer that the stringent species and tissue specificities observed for papillomaviruses in vivo are not entirely due to direct restrictions on viral DNA replication. Rather, transcriptional control of viral gene expression must play a dominant role.The initiation of DNA replication occurs at precisely defined origins (ori) to which specific control proteins bind. Simian virus 40 (SV40) and polyomavirus have long been used as models for investigations of mammalian DNA replication. Initiation of SV40 or polyomavirus replication requires the homologous large tumor antigen, is species specific, and occurs only in a permissive cell environment (1-4). However, the uncontrolled replication of these lytic viruses does not reflect the precise regulation of cellular DNA replication, which takes place once per cell cycle in the S phase. In contrast, papillomaviruses have regulated and uncontrolled replication phases during their life cycle and therefore offer a unique opportunity to study eukaryotic DNA replication.Human papillomavirus (HPV) types trophic for mucosal epithelia, including HPV-11, are highly infectious pathogens that cause genital warts and laryngeal papillomatosis. A subset of the genital types, including HPV-16 and -18, is also associated with the development of neoplasia and progression to cancer. In subclinical or benign infections, viral DNA persists as low-copy-number plasmids in the nuclei of the undifferentiated basal stem cells. Productive replication takes place only in the more differentiated upper strata of the epithelium. Although a culture system has recently been developed in which preinfected tissues produce progeny HPV-11 virions (25), propagation of HPVs has not been achieved in vitro starting from virions or transfected DNA. In transfected or infected cells, HPV DNA either integrates into host chromosomes or is lost. Therefore it has not been possible, until now, to perform molecular studies of autonomous HPV DNA replication in cell culture.In contrast, bovine papillomavirus type 1 (BPV-1) in transformed rodent cell lines replicates extrachromosomally at a constan...

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“…Enhanced synthesis of nicked circle structures occurred. Addition of ligase along with increasing amounts of ATP resulted in the formation of higher amounts of topoisomers (lanes [6][7][8]. The ratio of the total amounts of topoisomers and nicked circles was 6:4 at an ATP concentration of 4 mM (lane 8).…”

Section: Replicative Products Analysed In Non-denaturing Conditionsmentioning

confidence: 99%

Characterisation and mode of in vitro replication of pea chloroplast OriA sequences

Reddy

Choudhury

Kumar

et al. 1994

European Journal of Biochemistry

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A partially purified replicative system of pea chloroplast that replicates recombinant DNAs containing pea chloroplast origin sequences has been characterised. Polymerisation by this system is very fast and insensitive to chain terminators like dideoxynucleotides, arabinosylcytosine 5'-triphosphate, etc. Both strands of template DNA are synthesized and single-stranded DNA templates undergo more than one round of replication.When sequences of either of the two chloroplast origins of replication (OriA or OriB) are used as templates, the replicative intermediates are found to have sigma structures. Electron microscopic analysis of the sigma structures restricted with various enzymes reveals that the initiation site of in vitro replication maps near the displacement-loop regions where replication initiates also in vivo. Although the observed replication initiation in the OriA recombinant template is chloroplast-DNAspecific, the mode of replication is different from that observed in vivo with intact ctDNA. However, when the template DNA contains both the OriA and OriB sequences, the in vitro replication proceeds in the theta mode, the mode of replication usually observed in vivo.The complex process of DNA replication has been defined for only a few biological systems such as plasmids, bacteriophages, bacteria and viruses [l-61. So far, little is known about the DNA replication processes in plant systems except for few reports in the field of plant organelles [7-111. Chloroplast DNA (ctDNA) of higher plants seems to be an attractive system for investigation of the molecular details of replication. The chloroplast genomic size of about 150 kb is large but not too large for recombinant manipulations and the genome exists in multiple copies. Understanding the molecular biology of ctDNA replication would not only reveal the detailed characteristics of this system [12-141 but also help solve problems related to stable transformation of the chloroplast organelle. Thus, development of an in vitro replication system derived from higher plant chloroplasts is important both in helping to define DNA metabolism in general as well as advancing the technology of transgenic plant production [15-181. Replicative intermediates of ctDNA from pea leaves have been well characterised using electron microscopic techniques [19]. In pea and maize ctDNA, it was shown that replication begins by forming two displacement loops (Dloops) which expand towards each other to form a theta structure. This small Cairns' structure then proceeds bi-directionally until termination takes place. Meeker et al. [20] have mapped the two replication origins or D-loops by electron Correspondence to S . K.

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Activation of BPV-1 replication in vitro by the transcription factor E2

Cited by 275 publications

References 28 publications

Mutations in the human papillomavirus type 16 E2 protein identify a region of the protein involved in binding to E1 protein

Mutations in the human papillomavirus type 16 E2 protein identify a region of the protein involved in binding to E1 protein

Viral E1 and E2 proteins support replication of homologous and heterologous papillomaviral origins.

Characterisation and mode of in vitro replication of pea chloroplast OriA sequences

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