scholarly journals Effects of poly[d(pGpT).d(pApC)] and poly[d(pCpG).d(pCpG)] repeats on homologous recombination in somatic cells.

1986 ◽  
Vol 6 (11) ◽  
pp. 3948-3953 ◽  
Author(s):  
P Bullock ◽  
J Miller ◽  
M Botchan
Keyword(s):  
Homologous Recombination ◽  
Recombination Event ◽  
Somatic Cells ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Wild Type ◽  
Recombination Product ◽  
Homologous Recombination Event ◽  
Sequencing Studies ◽  
Purine Pyrimidine

Sequencing studies have shown that in somatic cells alternating runs of purines and pyrimidines are frequently associated with recombination crossover points. To test whether such sequences actually promote recombination, we have examined the effects of poly[d(pGpT).d(pApC)] and poly[d(pCpG).d(pCpG)] repeats on a homologous recombination event. The parental molecule used in this study, pSVLD, is capable of generating wild-type simian virus 40 DNA via recombination across two 751-base-pair regions of homology and has been described previously (Miller et al., Proc. Natl. Acad. Sci. USA 81:7534-7538, 1984). Single inserts of either a poly[d(pGpT).d(pApC)] repeat or a poly[d(pCpG).d(pCpG)] repeat were positioned adjacent to one region of homology in such a way that the recombination product, wild-type simian virus 40 DNA, could be formed only by recombination within the homologies and not by recombination across the alternating purine-pyrimidine repeats. We have found that upon transfection of test DNAs into simian cells, a poly[d(pCpG).d(pCpG)] repeat enhanced homologous recombination 10- to 15-fold, whereas a poly[d(pGpT).d(pApC)] repeat had less effect. These results are discussed in terms of the features of these repeats that might be responsible for promoting homologous recombination.

Effects of poly[d(pGpT).d(pApC)] and poly[d(pCpG).d(pCpG)] repeats on homologous recombination in somatic cells

1986 ◽  
Vol 6 (11) ◽  
pp. 3948-3953
Author(s):  
P Bullock ◽  
J Miller ◽  
M Botchan
Keyword(s):  
Homologous Recombination ◽  
Recombination Event ◽  
Somatic Cells ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Wild Type ◽  
Recombination Product ◽  
Homologous Recombination Event ◽  
Sequencing Studies ◽  
Purine Pyrimidine

Sequencing studies have shown that in somatic cells alternating runs of purines and pyrimidines are frequently associated with recombination crossover points. To test whether such sequences actually promote recombination, we have examined the effects of poly[d(pGpT).d(pApC)] and poly[d(pCpG).d(pCpG)] repeats on a homologous recombination event. The parental molecule used in this study, pSVLD, is capable of generating wild-type simian virus 40 DNA via recombination across two 751-base-pair regions of homology and has been described previously (Miller et al., Proc. Natl. Acad. Sci. USA 81:7534-7538, 1984). Single inserts of either a poly[d(pGpT).d(pApC)] repeat or a poly[d(pCpG).d(pCpG)] repeat were positioned adjacent to one region of homology in such a way that the recombination product, wild-type simian virus 40 DNA, could be formed only by recombination within the homologies and not by recombination across the alternating purine-pyrimidine repeats. We have found that upon transfection of test DNAs into simian cells, a poly[d(pCpG).d(pCpG)] repeat enhanced homologous recombination 10- to 15-fold, whereas a poly[d(pGpT).d(pApC)] repeat had less effect. These results are discussed in terms of the features of these repeats that might be responsible for promoting homologous recombination.

scholarly journals Specific Mismatch Recognition in Heteroduplex Intermediates by p53 Suggests a Role in Fidelity Control of Homologous Recombination

1998 ◽  
Vol 18 (9) ◽  
pp. 5332-5342 ◽  
Author(s):  
Christine Dudenhöffer ◽  
Gabor Rohaly ◽  
Katrin Will ◽  
Wolfgang Deppert ◽  
Lisa Wiesmüller
Keyword(s):  
Homologous Recombination ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Wild Type ◽  
Base Pairs ◽  
Recombination Processes ◽  
Quantitative Manner ◽  
Mismatch Recognition ◽  
Dna Substrate ◽  
Recombination Experiments

ABSTRACT We demonstrate that wild-type p53 inhibits homologous recombination. To analyze DNA substrate specificities in this process, we designed recombination experiments such that coinfection of simian virus 40 mutant pairs generated heteroduplexes with distinctly unpaired regions. DNA exchanges producing single C-T and A-G mismatches were inhibited four- to sixfold more effectively than DNA exchanges producing G-T and A-C single-base mispairings or unpaired regions of three base pairs comprising G-T/A-C mismatches. p53 bound specifically to three-stranded DNA substrates, mimicking early recombination intermediates. The KD values for the interactions of p53 with three-stranded substrates displaying differently paired and unpaired regions reflected the mismatch base specificities observed in recombination assays in a qualitative and quantitative manner. On the basis of these results, we would like to advance the hypothesis that p53, like classical mismatch repair factors, checks the fidelity of homologous recombination processes by specific mismatch recognition.

scholarly journals Rescue of chromosomal T-antigen sequences onto extrachromosomally replicating, defective simian virus 40 DNA by homologous recombination.

1986 ◽  
Vol 6 (4) ◽  
pp. 1320-1325 ◽  
Author(s):  
S Subramani
Keyword(s):  
Homologous Recombination ◽  
Dna Sequences ◽  
Base Pair ◽  
Recombination Event ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Extrachromosomal Dna ◽  
Cos Cells ◽  
Antigen Gene

Recombination between chromosomal and extrachromosomal DNA sequences was analyzed by investigation of the recombinational rescue of a 1,018-base-pair (bp) segment of the T-antigen gene of simian virus 40 from the chromosome of monkey COS cells to two different, extrachromosomally replicating, simian virus 40 DNA molecules lacking this 1,018-bp sequence. The ratio of rescued to unrecombined virus was as high as 10(-3). The rescued molecules, detected optimally 5 to 9 days after transfection of COS cells, had completely recovered the 1,018-bp DNA segment from the chromosome. The recombination event is proposed to occur either by double reciprocal recombination or by gene conversion between the chromosomal T-antigen gene and the extrachromosomal molecules missing the 1,018-bp sequence.

scholarly journals Ectopic recombination within homologous immunoglobulin mu gene constant regions in a mouse hybridoma cell line.

1992 ◽  
Vol 12 (10) ◽  
pp. 4422-4432 ◽  
Author(s):  
M D Baker ◽  
L R Read
Keyword(s):  
Homologous Recombination ◽  
Recombination Event ◽  
Mutant Cell ◽  
Immunoglobulin M ◽  
Constant Region ◽  
Wild Type ◽  
Ectopic Recombination ◽  
The Third ◽  
Homologous Recombination Event ◽  
Immunoglobulin Mu

We have transferred a pSV2neo vector containing the wild-type constant region of the immunoglobulin mu gene (C mu) into the mutant hybridoma igm482, which bears a 2-bp deletion in the third constant-region exon of its haploid chromosomal mu gene (C mu 3). Independent igm482 transformants contain the wild-type immunoglobulin C mu region stably integrated in ectopic chromosomal positions. We report here that the wild-type immunoglobulin C mu region can function as the donor sequence in a gene conversion event which corrects the 2-bp deletion in the mutant igm482 chromosomal C mu 3 exon. The homologous recombination event restores normal immunoglobulin M production in the mutant cell.

scholarly journals Induction of Duplication Reversion in Human Fibroblasts, by Wild-Type and Mutated SV40 T Antigen, Covaries With the Ability to Induce Host DNA Synthesis

Genetics ◽  
1997 ◽  
Vol 146 (4) ◽  
pp. 1417-1428
Author(s):  
Masood A Shammas ◽  
Shujuan J Xia ◽  
Robert J Shmookler Reis
Keyword(s):  
Homologous Recombination ◽  
Dna Synthesis ◽  
Human Fibroblasts ◽  
Point Mutations ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Hypoxanthine Phosphoribosyl Transferase ◽  
Wild Type ◽  
Chromosomal Recombination

Intrachromosomal homologous recombination, manifest as reversion of a 14-kbp duplication in the hypoxanthine phosphoribosyl transferase (HPRT) gene, is elevated in human cells either stably transformed or transiently transfected by the SV40 (simian virus 40) large T antigen gene. Following introduction of wild-type SV40, or any of several T-antigen point mutations in a constant SV40 background, we observed a strong correlation between the stimulation of chromosomal recombination and induction of host-cell DNA synthesis. Moreover, inhibitors of DNA replication (aphidicolin and hydroxyurea) suppress SV40-induced homologous recombination to the extent that they suppress DNA synthesis. Stable integration of plasmids encoding T antigen also augments homologous recombination, which is suppressed by aphidicolin. We infer that the mechanism by which T antigen stimulates homologous recombination in human fibroblasts involves DNA replicative synthesis.

Ectopic recombination within homologous immunoglobulin mu gene constant regions in a mouse hybridoma cell line

1992 ◽  
Vol 12 (10) ◽  
pp. 4422-4432
Author(s):  
M D Baker ◽  
L R Read
Keyword(s):  
Homologous Recombination ◽  
Recombination Event ◽  
Mutant Cell ◽  
Immunoglobulin M ◽  
Constant Region ◽  
Wild Type ◽  
Ectopic Recombination ◽  
The Third ◽  
Homologous Recombination Event ◽  
Immunoglobulin Mu

We have transferred a pSV2neo vector containing the wild-type constant region of the immunoglobulin mu gene (C mu) into the mutant hybridoma igm482, which bears a 2-bp deletion in the third constant-region exon of its haploid chromosomal mu gene (C mu 3). Independent igm482 transformants contain the wild-type immunoglobulin C mu region stably integrated in ectopic chromosomal positions. We report here that the wild-type immunoglobulin C mu region can function as the donor sequence in a gene conversion event which corrects the 2-bp deletion in the mutant igm482 chromosomal C mu 3 exon. The homologous recombination event restores normal immunoglobulin M production in the mutant cell.

Rescue of chromosomal T-antigen sequences onto extrachromosomally replicating, defective simian virus 40 DNA by homologous recombination

1986 ◽  
Vol 6 (4) ◽  
pp. 1320-1325
Author(s):  
S Subramani
Keyword(s):  
Homologous Recombination ◽  
Dna Sequences ◽  
Base Pair ◽  
Recombination Event ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Extrachromosomal Dna ◽  
Cos Cells ◽  
Antigen Gene

Recombination between chromosomal and extrachromosomal DNA sequences was analyzed by investigation of the recombinational rescue of a 1,018-base-pair (bp) segment of the T-antigen gene of simian virus 40 from the chromosome of monkey COS cells to two different, extrachromosomally replicating, simian virus 40 DNA molecules lacking this 1,018-bp sequence. The ratio of rescued to unrecombined virus was as high as 10(-3). The rescued molecules, detected optimally 5 to 9 days after transfection of COS cells, had completely recovered the 1,018-bp DNA segment from the chromosome. The recombination event is proposed to occur either by double reciprocal recombination or by gene conversion between the chromosomal T-antigen gene and the extrachromosomal molecules missing the 1,018-bp sequence.

scholarly journals A splice junction deletion deficient in the transport of RNA does not polyadenylate nuclear RNA.

1983 ◽  
Vol 3 (8) ◽  
pp. 1381-1388 ◽  
Author(s):  
L P Villarreal ◽  
R T White
Keyword(s):  
Simian Virus 40 ◽  
Splice Junction ◽  
Simian Virus ◽  
The Body ◽  
Splice Acceptor Site ◽  
Acceptor Site ◽  
Wild Type ◽  
Normal Position ◽  
Nuclear Rna ◽  
Late Region

A late region deletion mutant of simian virus 40 (dl5) was previously shown to be deficient in the transport of nuclear RNA. This is a splice junction deletion that has lost the 3' end of an RNA leader, an intervening sequence, and the 5' end of the splice acceptor site on the body of the mRNA. In this report, we analyzed the steady-state structure of the untransported nuclear RNA. The 5' ends of this RNA are heterogeneous but contain a prominent 5' end at the normal position (nucleotide 325) in addition to several other prominent 5' ends not seen in wild-type RNA. The 3' end of this RNA does not occur at the usual position (nucleotide 2674) of polyadenylation; instead, this RNA is non-polyadenylated, with the 3' end occurring either downstream or upstream of the normal position.

The number of ribosomes on simian virus 40 late 16S mRNA is determined in part by the nucleotide sequence of its leader

1984 ◽  
Vol 4 (4) ◽  
pp. 813-816
Author(s):  
A Barkan ◽  
J E Mertz
Keyword(s):  
Nucleotide Sequence ◽  
Direct Evidence ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
The Body ◽  
Size Distributions ◽  
Wild Type ◽  
Leader Protein ◽  
16S Rna

The size distributions of polyribosomes containing each of three simian virus 40 late 16S mRNA species that differ in nucleotide sequence only within their leaders were determined. The two 16S RNA species with shorter leaders were incorporated into polysomes that were both larger (on average) and narrower in size distribution than was the predominant wild-type 16S RNA. Therefore, the nucleotide sequence of the leader can influence the number of ribosomes present on the body of an mRNA molecule. We propose a model in which the excision from leaders of sizeable translatable regions permits more frequent utilization of internally located translation initiation signals, thereby enabling genes encoded within the bodies of polygenic mRNAs to be translated at higher rates. In addition, the data provide the first direct evidence that VP1 can, indeed, be synthesized in vivo from the species of 16S mRNA that also encodes the 61-amino acid leader protein.

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