5-Azacytidine-induced hypomethylation of tobacco HRS60 tandem DNA repeats in tissue culture

Bezděk, M.; Koukalová, B.; Brzobohatý, Břetislav; Vyskot, Boris

doi:10.1007/bf00197896

Cited by 31 publications

(6 citation statements)

References 26 publications

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“…In our studies treatment with 5-azc resulted in the loss of inner C methylation in many of the copies of the array. Similar observations have been made for rDNA in triticale [ 12] and repetitive DNA in tobacco [5]. Despite the perturbation of rDNA methylation state reported here, no obvious phenotypic alteration in treated plants was observed.…”

Section: Discussionsupporting

confidence: 91%

Promoter methylation and progressive transgene inactivation inArabidopsis

1992

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Agrobacterium-transformed Arabidopsis plants were generated and the stability of their T-DNA-encoded resistance to kanamycin was examined. Of seven families, each homozygous for a single insertion event, two showed progressive inactivation of resistance over four generations of inbreeding. Loss of resistance was associated with methylation of an Sst II site in the nos promoter of the kanamycin resistance gene. Treatment of plant roots from inactive lines with the demethylating agent 5-azacytidine restored the ability of such lines to form callus on kanamycin-containing media. These observations are consistent with the view that methylation is a factor in the progressive inactivation of transgenes in Arabidopsis.

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Section: Discussionsupporting

confidence: 91%

Promoter methylation and progressive transgene inactivation inArabidopsis

1992

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“…VielblaÈ ttriger were cultured on Murashige-Skoog's medium (BezdeÏ k et al 1991). After three 3-week periods of subculture, 500-mg pieces of calli were transferred to media containing 25 lM DHPA and grown for another 3 weeks (KovarÏ õÂ k et al 1994).…”

Section: Methodsmentioning

confidence: 99%

Mapping of 5-methylcytosine residues in Nicotiana tabacum 5S rRNA genes by genomic sequencing

et al. 1998

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Genomic sequencing was used to localise 5-methylcytosine residues in individual DNA strands of 5S rRNA genes in tobacco. The density of methylation along the sequence was high in both strands, exceeding the average methylation density of the tobacco genome. Besides methylation of CG and CNG sequences, considerable amounts of mC were found in non-symmetrical sites. Among 69 sequenced clones obtained from leaf DNA we did not detect any non-methylated clone, and Southern blot hybridisation analysis also failed to suggest the presence of methylation-free 5S rDNA units in the tobacco genome. Differences were observed among methylation patterns of individual sequenced clones. This heterogeneity reflects either heterogeneity among individual members of 5S rRNA gene cluster or differences among individual cells. Methylation of CNG and non-symmetrical sites can be efficiently reduced by treatment with dihydroxypropyladenine, an inhibitor of S-adenosylhomocysteine hydrolase.

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“…These results are in agreement with that obtained using LUMA. 5-Aza an analog of 5-methylcytosine, is commonly used as a hypomethylation agent (Bezdek et al, 1991;Christman, 2002). Therefore we used 5-aza in our experiments as a positive control of hypomethylation.…”

Section: The Effect Of Juglone On the Changes Of Dna Methylationmentioning

confidence: 99%