Separation of the transcriptional activation and replication functions of the bovine papillomavirus-1 E2 protein.

Winokur, Patricia L.; McBride, A A

doi:10.1002/j.1460-2075.1992.tb05504.x

Cited by 57 publications

(63 citation statements)

References 49 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The mutations tested were those cloned into the full-length LCR background of p1066 (p2702 and p2703). The plasmids were co-transfected into primary BEF cells or CV-1 cells alone or with either the E2-expressing plasmid pC59 (+E2) or the plasmid pC59.Kpn.TTL (-E2), which contains a translation termination linker inserted into the E2 coding region and results in the production of a non-functional E2 protein (Winokur & McBride, 1992). As before, the transfection was also performed in CV-1 cells to ensure that any reduced level of E2 transactivation observed with plasmids p2702 and p2703 was not simply due to a complete lack of basal activity.…”

Section: Resultsmentioning

confidence: 99%

Sp1 is critical for basal and E2-transactivated transcription from the bovine papillomavirus type 1 P89 promoter

Sandler

Baker

Spalholz³

1996

Journal of General Virology

View full text Add to dashboard Cite

The bovine papillomavirus type 1 (BPV-1) long control region (LCR) contains at least three consensus binding sites for the transcription factor Sp 1 at nucleotides (nt) 7800, 7833 and 7854. A high basal-level Pso expression vector consisting of an origin-deleted LCR fused to the chloramphenicol acetyltransferase (CAT) gene was utilized to determine the role of these Spl sites in the regulation of transcription from the BPV-1 Ps,9 promoter. The three Spl sites were capable of binding Spl in vitro.Mutation of these sites in the background of the origindeleted LCR-CAT or a wild-type LCR-CAT construct resulted in decreased basal expression from Psg-In addition, mutation of the Spl sites in the wild-type background caused a reduction in E2-transactivation potential. These data illustrate the importance of these Spl sites in regulating both basal and E2-transactivated Ps9 expression.

show abstract

Section: Resultsmentioning

confidence: 99%

Sp1 is critical for basal and E2-transactivated transcription from the bovine papillomavirus type 1 P89 promoter

Sandler

Baker

Spalholz³

1996

Journal of General Virology

View full text Add to dashboard Cite

show abstract

“…Deletion of any sequence within the domain inactivates the protein and many single amino acid substitutions are sufficient to disrupt the functions of the E2 proteins (2,31). Several mutations in the E2 transactivation domain have been shown to result in a temperature-sensitive phenotype for replication and transactivation (11,12).…”

Section: Discussionmentioning

confidence: 99%

Conditional Mutations in the Mitotic Chromosome Binding Function of the Bovine Papillomavirus Type 1 E2 Protein

Zheng

Brokaw

McBride

2005

J Virol

View full text Add to dashboard Cite

The papillomavirus E2 protein is required for viral transcriptional regulation, DNA replication and genome segregation. We have previously shown that the E2 transactivator protein and BPV1 genomes are associated with mitotic chromosomes; E2 links the genomes to cellular chromosomes to ensure efficient segregation to daughter nuclei. The transactivation domain of the E2 protein is necessary and sufficient for association of the E2 protein with mitotic chromosomes. To determine which residues of this 200-amino-acid domain are important for chromosomal interaction, E2 proteins with amino acid substitutions in each conserved residue of the transactivation domain were tested for their ability to associate with mitotic chromosomes. Chromatin binding was assessed by using immunofluorescence on both spread and directly fixed mitotic chromosomes. E2 proteins defective in the transactivation and replication functions were unable to associate with chromosomes, and those that were competent in these functions were attached to mitotic chromosomes. However, several mutated proteins that were defective for chromosomal interaction could associate with chromosomes after treatment with agents that promote protein folding or when cells were incubated at lower temperatures. These results indicate that precise folding of the E2 transactivation domain is crucial for its interaction with mitotic chromosomes and that this association can be modulated.Papillomavirus are small DNA viruses that cause persistent epithelial lesions called papillomas (15). Papillomavirus genomes are maintained as multicopy episomes in the proliferating basal layers of papillomas; viral DNA amplification and virion particle production occur only as infected cells differentiate in the stratified epithelium. Episomal viral genomes are retained in the nucleus and are segregated between daughter cells because they are attached to condensed cellular chromosomes in mitotic cells (18,20,26). This interaction is mediated by the E2 transactivator protein (E2-TA), which acts as a link to tether viral DNA onto mitotic chromosomes.In addition to its role in genome retention and segregation, the E2-TA protein regulates viral transcription and DNA replication. In bovine papillomavirus type 1 (BPV1), the E2 gene encodes three different polypeptides (22). The largest protein, expressed from the entire E2 open reading frame and designated E2-TA, is a transcriptional transactivator and is required for viral DNA replication. The two smaller E2 proteins, E2-TR and E8/E2, are encoded by the 3Ј half of the E2 open reading frame and function as transcriptional repressors. The E2-TA protein contains two conserved functional domains: a N-terminal transactivation domain of ca. 200 amino acids and Cterminal DNA-binding domain and dimerization domain of ca. 100 residues. These domains are linked by a flexible hinge region. Only the E2-TA species of E2 protein is localized on mitotic chromosomes, and this interaction is mediated by the transactivation domain (6, 26).The transactivation d...

show abstract

“…While the rRNA promoter is not absolutely required for transformation of Tetrahymena rDNA plasmids, its presence increases the transformation efficiency of rDNA origin constructs (13). Hence, the complex at the rDNA promoter of the Tetrahymena rDNA minichromosome may be functionally analogous to that involving the BPV transcriptional activator BPV E2, which complexes with the DNA replication initiation protein E1 at the BPV replication origin (40,43,47,49). An rDNA complex might similarly facilitate binding of E1-analogous factors at the repeat 1-2 origin region.…”

Section: Discussionmentioning

confidence: 99%

A Promoter Region Mutation Affecting Replication of the Tetrahymena Ribosomal DNA Minichromosome

Gallagher

Blackburn

1998

Molecular and Cellular Biology

View full text Add to dashboard Cite

In the ciliated protozoan Tetrahymena thermophila the ribosomal DNA (rDNA) minichromosome replicates partially under cell cycle control and is also subject to a copy number control mechanism. The relationship between rDNA replication and rRNA gene transcription was investigated by the analysis of replication, transcription, and DNA-protein interactions in a mutant rDNA, the rmm3 rDNA. The rmm3 (for rDNA maturation or maintenance mutant 3) rDNA contains a single-base deletion in the rRNA promoter region, in a phylogenetically conserved sequence element that is repeated in the replication origin region of the rDNA minichromosome. The multicopy rmm3 rDNA minichromosome has a maintenance defect in the presence of a competing rDNA allele in heterozygous cells. No difference in the level of rRNA transcription was found between wild-type and rmm3 strains. However, rmm3 rDNA replicating intermediates exhibited an enhanced pause in the region of the replication origin, roughly 750 bp upstream from the rmm3 mutation. In footprinting of isolated nuclei, the rmm3 rDNA lacked the wild-type dimethyl sulfate (DMS) footprint in the promoter region adjacent to the base change. In addition, a DMS footprint in the origin region was lost in the rmm3 rDNA minichromosome. This is the first reported correlation in this system between an rDNA minichromosome maintenance defect and an altered footprint in the origin region. Our results suggest that a promoter region mutation can affect replication without detectably affecting transcription. We propose a model in which interactions between promoter and origin region complexes facilitate replication and maintenance of the Tetrahymena rDNA minichromosome.

show abstract

Separation of the transcriptional activation and replication functions of the bovine papillomavirus-1 E2 protein.

Cited by 57 publications

References 49 publications

Sp1 is critical for basal and E2-transactivated transcription from the bovine papillomavirus type 1 P89 promoter

Sp1 is critical for basal and E2-transactivated transcription from the bovine papillomavirus type 1 P89 promoter

Conditional Mutations in the Mitotic Chromosome Binding Function of the Bovine Papillomavirus Type 1 E2 Protein

A Promoter Region Mutation Affecting Replication of the Tetrahymena Ribosomal DNA Minichromosome

Contact Info

Product

Resources

About