scholarly journals Transcription factor Oct1 binds to the AT-rich segment of the simian virus 40 replication origin.

1995 ◽  
Vol 69 (1) ◽  
pp. 575-578 ◽  
Author(s):  
J Kilwinski ◽  
M Baack ◽  
S Heiland ◽  
R Knippers
Keyword(s):  
Transcription Factor ◽  
Replication Origin ◽  
Simian Virus 40 ◽  
Simian Virus

scholarly journals Composite patterns in neutral/neutral two-dimensional gels demonstrate inefficient replication origin usage.

1996 ◽  
Vol 16 (9) ◽  
pp. 4915-4922 ◽  
Author(s):  
R F Kalejta ◽  
J L Hamlin
Keyword(s):  
Replication Origin ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Yeast Cells ◽  
Eukaryotic Cells ◽  
Mapping Technique ◽  
Two Dimensional ◽  
Composite Pattern ◽  
Composite Gel ◽  
Bona Fide

The neutral/neutral two-dimensional (2-D) gel replicon mapping technique has been used to great advantage to localize and characterize origins of replication. Interestingly, many yeast origins display a composite pattern consisting of both a bubble arc and a single-fork arc. Moreover, in every instance in which neutral/neutral 2-D gels have been used to analyze origins in higher eukaryotic cells, two or more adjacent fragments display these composite patterns. We believe that composite patterns signal inefficient origin usage in yeast cells because the replicators in question are not active in every cell cycle and in higher eukaryotic replicons because initiation sites are chosen from among many potential sites lying within a zone. However, others have suggested that the single-fork arcs in these composite gel patterns arise from nicking activity that converts replication bubbles to branched structures that comigrate with bona fide single forks. Here, we have used three different replicon mapping strategies to show that broken simian virus 40 replication bubbles trace unique arcs that are clearly distinguishable from classic, intact single forks. Thus, it is likely that composite 2-D gel patterns represent origins that are inefficiently utilized.

Specific transcription factors stimulate simian virus 40 and polyomavirus origins of DNA replication

1992 ◽  
Vol 12 (6) ◽  
pp. 2514-2524 ◽  
Author(s):  
Z S Guo ◽  
M L DePamphilis
Keyword(s):  
Transcription Factor ◽  
Transcription Factors ◽  
Dna Replication ◽  
Binding Sites ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Activation Domains ◽  
Auxiliary Component ◽  
Cell Extracts

The origins of DNA replication (ori) in simian virus 40 (SV40) and polyomavirus (Py) contain an auxiliary component (aux-2) composed of multiple transcription factor binding sites. To determine whether this component stimulated replication by binding specific transcription factors, aux-2 was replaced by synthetic oligonucleotides that bound a single transcription factor. Sp1 and T-antigen (T-ag) sites, which exist in the natural SV40 aux-2 sequence, provided approximately 75 and approximately 20%, respectively, of aux-2 activity when transfected into monkey cells. In cell extracts, only T-ag sites were active. AP1 binding sites could replace completely either SV40 or Py aux-2. Mutations that eliminated AP1 binding also eliminated AP1 stimulation of replication. Yeast GAL4 binding sites that strongly stimulated transcription in the presence of GAL4 proteins failed to stimulate SV40 DNA replication, although they did partially replace Py aux-2. Stimulation required the presence of proteins consisting of the GAL4 DNA binding domain fused to specific activation domains such as VP16 or c-Jun. These data demonstrate a clear role for transcription factors with specific activation domains in activating both SV40 and Py ori. However, no correlation was observed between the ability of specific proteins to stimulate promoter activity and their ability to stimulate origin activity. We propose that only transcription factors whose specific activation domains can interact with the T-ag initiation complex can stimulate SV40 and Py ori-core activity.

One exon of the human LSF gene includes conserved regions involved in novel DNA-binding and dimerization motifs

1994 ◽  
Vol 14 (8) ◽  
pp. 5076-5087
Author(s):  
M K Shirra ◽  
Q Zhu ◽  
H C Huang ◽  
D Pallas ◽  
U Hansen
Keyword(s):  
Transcription Factor ◽  
Dna Binding ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Binding Activity ◽  
Protein Protein Interaction ◽  
Dna Binding Activity ◽  
Dna Binding Sites ◽  
Alternative Mrna Splicing ◽  
Alternatively Spliced

The transcription factor LSF, identified as a HeLa protein that binds the simian virus 40 late promoter, recognizes direct repeats with a center-to-center spacing of 10 bp. The characterization of two human cDNAs, representing alternatively spliced mRNAs, provides insight into the unusual DNA-binding and oligomerization properties of LSF. The sequence of the full-length LSF is identical to that of the transcription factors alpha CP2 and LBP-1c and has similarity to the Drosophila transcription factor Elf-1/NTF-1. Using an epitope-counting method, we show that LSF binds DNA as a homodimer. LSF-ID, which is identical to LBP-1d, contains an in-frame internal deletion of 51 amino acids resulting from alternative mRNA splicing. Unlike LSF, LSF-ID did not bind LSF DNA-binding sites. Furthermore, LSF-ID did not affect the binding of LSF to DNA, suggesting that the two proteins do not interact. Of three short regions with a high degree of homology between LSF and Elf-1/NTF-1, LSF-ID lacks two, which are predicted to form beta-strands. Double amino acid substitutions in each of these regions eliminated specific DNA-binding activity, similarly to the LSF-ID deletion. The dimerization potential of these mutants was measured both by the ability to inhibit the binding of LSF to DNA and by direct protein-protein interaction studies. Mutations in one homology region, but not the other, functionally eliminated dimerization.

scholarly journals Mouse BTEB3, a new member of the basic transcription element binding protein (BTEB) family, activates expression from GC-rich minimal promoter regions

2000 ◽  
Vol 345 (3) ◽  
pp. 529-533 ◽  
Author(s):  
Karen M. MARTIN ◽  
Wendy N. COOPER ◽  
James C. METCALFE ◽  
Paul R. KEMP
Keyword(s):  
Transcription Factor ◽  
Transcription Factors ◽  
Zinc Finger ◽  
Binding Protein ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Minimal Promoter ◽  
Promoter Regions ◽  
Basal Transcription ◽  
Element Binding Protein

Members of the three-zinc-finger family of transcription factors play an important role in determining basal transcription. We have cloned mouse BTEB3 (mBTEB3), a new member of the basic transcription element binding protein (BTEB) family, which is expressed in a wide variety of tissues. mBTEB3 activates transcription of the simian virus 40 early promoter (4-fold) and of the tissue-specific SM22α promoter (100-fold), suggesting that, like BTEB1 and Sp1, mBTEB3 is a basal transcription factor.

scholarly journals Identification and characterization of multiple erythroid cell proteins that interact with the promoter of the murine alpha-globin gene.

1988 ◽  
Vol 8 (8) ◽  
pp. 3215-3226 ◽  
Author(s):  
K M Barnhart ◽  
C G Kim ◽  
S S Banerji ◽  
M Sheffery
Keyword(s):  
Transcription Factor ◽  
Binding Site ◽  
Binding Sites ◽  
Globin Gene ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Erythroid Cell ◽  
Alpha Globin ◽  
Murine Erythroleukemia

The proteins responsible for erythroid-specific footprints extending to -180 on the mouse alpha-globin gene were identified, enriched, and characterized from extracts of murine erythroleukemia (MEL) cells. Three proteins accounted for most aspects of the footprints. The binding sites of two proteins, termed alpha-CP1 and alpha-CP2, overlapped in the CCAAT box. Further characterization of these two CCAAT binding proteins showed that neither interacted with the adenovirus origin of replication, a strong CCAAT transcription factor-nuclear factor 1 binding site. A third protein, termed alpha-IRP, interacted with two sequences that formed an inverted repeat (IR) between the CCAAT and TATAA boxes. Interestingly, the binding domain of one of the CCAAT factors, alpha-CP1, overlapped one alpha-IRP binding site. alpha-CP1 thus overlapped the binding domains of both alpha-CP2 and alpha-IRP. The IRs included GC-rich sequences reminiscent of SP1-binding sites. Indeed, alpha-IRP bound as well to the alpha-promoter as it did to SP1 sites in the simian virus 40 early promoter. These results suggest that alpha-IRP may be related to the transcription factor Sp1. We determined the level of each alpha-globin-binding activity before and after induced erythroid differentiation of MEL cells. We found that differentiation caused alpha-CP1 activity to drop three- to fivefold, while alpha-IRP activity decreased slightly and alpha-CP2 activity increased two- to threefold.

scholarly journals Evolutionarily selected replication origins: functional aspects and structural organization.

1986 ◽  
Vol 6 (9) ◽  
pp. 3077-3085 ◽  
Author(s):  
G J Lee-Chen ◽  
M Woodworth-Gutai
Keyword(s):  
Inverted Repeat ◽  
Replication Origin ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Inverted Repeats ◽  
Regulatory Sequences ◽  
Functional Aspects ◽  
Cellular Sequence ◽  
Transfection Mixture

A selective replicative pressure occurs during the evolution of simian virus 40 variants. When the replication origin is duplicated as an inverted repeat, there is a dramatic enhancement of replication. Having regulatory sequences located between the inverted repeat of ori magnifies their enhancing effect on replication. A passage 20 variant and a passage 45 variant containing three pairs of an inverted repeat of ori replicated more efficiently than a passage 13 variant containing nine copies of ori arranged in tandem. A 69-base-pair cellular sequence inserted between inverted repeats of ori of both passage 40 and 45 variants enhanced simian virus 40 DNA replication. Differences in replication efficiencies became greater as the total number of replicating species was increased in the transfection mixture, under conditions where T antigen is limiting. In a competitive environment, sequences flanking the replication origin may be inhibitory to replication.

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