ISSN:
1573-5028
Keywords:
DNA methylation
;
5-methylcytosine
;
uracil excision
;
DNA mismatch repair
;
geminivirus
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract We have compared the fate of U · G mispairs or analogous T · G mispairs in DNA heteroduplexes transfected into tobacco protoplasts. The heteroduplex DNA consisted of tomato golden mosaic virus DNA sequences in theEscherichia coli vectors pUC118 or pUC119. After transfection, the mismatched U residues were lost with an efficiency of greater than 95%, probably as a result of the uracil-DNA glycosylase pathway for excision of U residues in any sequence context. In contrast to the preferential removal of the mispaired U residues, biased removal of T residues from analogous heteroduplexes was not seen in the transfected plant cells. Also, we investigated the effect of extensively methylating one strand of the heteroduplex DNA used for transfection. Surprisingly, such methylation resulted in highly biased loss of the mismatched base from the 5-methylcytosine-rich strand of T · G-containing heteroduplexes.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00029155
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