Modification of avian sarcoma proviral DNA sequences in nonpermissive XC cells but not in permissive chicken cells

Guntaka, Ramareddy V.; Rao, Prasad Y.; Mitsialis, S. Alex; Katz, Richard A.

doi:10.1128/jvi.34.2.569-572.1980

Cited by 55 publications

(11 citation statements)

References 20 publications

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“…Many authors agree that genes that are transcriptionnaly active are undermethylated in their DNA, while untranscribed genes are overmethylated (7,(13)(14)(15)(16)25,32,33). We may also make this correlation, i.e.…”

Section: Discussionmentioning

confidence: 95%

“…Variations in the methylation pattern within and around globin genes in different tissues have been reported in chicken (12,13), in man (7) and in rabbit (14). In transformed cells, the methylation of proviral genomes (15,16) and the level of methylation of the DNA of the transformed tissue itself (17) has been investigated. However, these studies have not yet been extended to a specific cellular gene whose function is affected after transformation by an RNA tumor virus.…”

Section: Introductionmentioning

confidence: 99%

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Modification of the methylation pattern in the vicinity of the chicken globin genes in avian erythroblastosis virus transformed cells

et al. 1981

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Having previously found a reduced transcription of globin genes and an abortive processing of the already transcribed globin pre-mRNA in Avian Erythroblastosis Virus (AEV) transformed cells (1), we compared the genomic DNA of these cells with that of normal chicken erythroblasts, using 32-P-labelled cDNA probes specific for the beta, alpha A and alpha D globin sequences. Restriction endonuclease digestion, electrophoresis of digests in agarose gels, Southern blotting and hybridization were carried out. Our results show that the overall genome organization is not disturbed in the immediate neighbourhood of the adult globin genes; the observed restriction fragments are identical for both DNAs after EcoRI, HindIII, BamHI and XbaI digestion, using the beta, alpha A and alpha D globin cDNA probes. However, we observe specific modifications at some methylation sites in the beta, beta-like and alpha D regions: after HpaII or MspI digestion in the alpha D region and after HhaI digestion in the beta and beta-like region, heavier bands appear in the transformed cell DNA in addition to the ones observed in normal DNA. This implies that, at some specific sites, the transformed cell DNA is more methylated than the normal erythroblast DNA. The possible significance of this observation is discussed.

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Section: Discussionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Modification of the methylation pattern in the vicinity of the chicken globin genes in avian erythroblastosis virus transformed cells

et al. 1981

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“…Studies of DNA modification have indicated that the extent of methylation of both cellular and viral DNAs is correlated with gene expression in that inactive genes are frequently highly methylated (6,15,23,33). However, it is not clear whether DNA methylation directly affects gene expression, particularly since recent studies have indicated a lack of correlation between methylation and transcriptional activity of sea urchin histone genes (4) and of human globin genes in some tissues and cell lines (33).…”

Section: Discussionmentioning

confidence: 99%

Integration, expression, and infectivity of exogenously acquired proviruses of Rous-associated virus-O

Jenkins

Cooper

1980

J Virol

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We investigated the integration sites, infectivities, and expression of Rous-associated virus-0 (Rav-0) DNAs in exogenously infected turkey and chicken cells. Restriction endonuclease analyses of the DNAs of RAV-0-infected cells indicated that unique integration sites of RAV-0 DNA were detectable in clones of RAV-0-infected cells but not in mass-infected cell cultures. In addition, the sites of integration of RAV-0 DNA differed in each of the seven clones of RAV-0-infected cells examined. Thus, endogenous RAV-0 proviruses appeared to integrate at multiple sites in cellular DNA, which were distinct from the sites of integration of endogenous RAV-0 genomes. Since exogenous RAV-0 proviruses are expressed at 10(3)- to 10(4)-fold-higher levels and are 10(3)- to 10(4)-fold more infectious in transfection assays than the endogenous RAV-0 genome of uninfected V+ chicken cells, these results are consistent with the hypothesis that transcription of the endogenous RAV-0 genome is regulated by flanking cellular DNA sequences. Although all RAV-0-infected cells contained infectious RAV-0 DNA and produced high titers of RAV-0 compared with uninfected V+ cells, different clones of RAV-0 infected chicken cells differed by as much as 30-fold in their levels of virus production. The infectivity of the DNA of each clone of RAV-0-infected cells correlated with the amount of virus produced by that clone. However, these differences did not appear to be correlated either with the number of exogenous RAV-0 proviruses in different clones or with the infectivity of RAV-0 produced by different clones, indicating that differences either in modification of RAV-0 DNAs or in the cellular sequences flanking exogenous RAV-0 DNAs were responsible for the observed differences in expression and infectivity.

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“…4, lanes 4 and 5) ranging in size from 0.5 to 25 kb could be readily observed in plasmodium DNA, strongly suggesting that the repeat sequence is Plasmodium-specific. It should be pointed out that only 2 to 3 pg Plasmodium DNA was used in these experiments as opposed to [15][16][17][18][19][20] pg of human and mouse DNAs. Even with these smaller amounts of plasmodium DNA, repeat sequence-specific bands could be detected only after 15 minute exposure; an example of these results after a 2 hour exposure is given in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…x Denhardt buffer, 3 mM EDTA, 100 pg/ml denatured calf thymus or herring sperm DNA) was used at 680C for 18 to 20 hours. The filters were washed, dried and exposed to Kodak X.O.Mat AR film with intensifying screen as described previously (16).…”

Section: Methodsmentioning

confidence: 99%

Organization ofPlasmodium falciparum genome: 1. Evidence for a highly repeated DNA sequence

et al. 1985

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Plasmodium falciparum DNA, isolated from the merozoite stage, was cleaved with HindIII and cloned in pBR322 and lambda L47.1 vectors. Plasmid clones containing 13.4, 7.0, 4.3, 4.1 and 1.5 kb inserts were characterized in some detail. The inserts contain several repeating units of smaller size. Nucleic acid hybridization studies showed that the repeat element is present in the Plasmodium DNA at a very high copy number and appears to be distributed widely throughout the genome.

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Modification of avian sarcoma proviral DNA sequences in nonpermissive XC cells but not in permissive chicken cells

Cited by 55 publications

References 20 publications

Modification of the methylation pattern in the vicinity of the chicken globin genes in avian erythroblastosis virus transformed cells

Modification of the methylation pattern in the vicinity of the chicken globin genes in avian erythroblastosis virus transformed cells

Integration, expression, and infectivity of exogenously acquired proviruses of Rous-associated virus-O

Organization ofPlasmodium falciparum genome: 1. Evidence for a highly repeated DNA sequence

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