Evaluation of the impact of S‐adenosylhomocysteine metabolic pools on cytosine methylation of the tobacco genome

摘要: We explored the possibility that cytosine DNA methylation might be regulated by S-adenosyl- L-methionine (AdoMet) and L-homocysteine (AdoHcy) pools in plant cells. In order to change AdoHcy/AdoMet ratio (methylation index), (S)-9-(2,3-dihydroxypropyl)adenine was employed, a selective reversible inhibitor of cellular hydrolase. Micromolar concentrations increased dramatically (more than 1000-fold) intracellular AdoHcy levels (and concominantly ratio) tobacco TBY-2 No toxic effect drug observed cells displayed only marginal inhibition growth at high levels. At near equal AdoMet, significant reduction transcribed (5SrDNA) non-transcribed (HRS60, NTRS) sequences observed. Interestingly, CpCpG CpApG trinucleotide targets appeared most sensitive changes index. Methylation residues CpG sites not affected even > 10. These results support possible regulation via metabolic pathways