Abstracts (poster) - Wissenschaft Online

Madeleine Meusburger, Mark Helm, Frank Lyko
tRNA targets methylated by the Dnmt2 methyltransferase
Dnmt2 is the most widely conserved member of the family of DNA methyltransferases.
The protein contains ten catalytic motifs that are characteristic for DNA methylating
enzymes. However, the molecular and biological functions of Dnmt2 have remained
enigmatic. It has been shown that the DNA methylating activity is very low in vitro,
which contrasts with its readily detectable methylation of cytosine 38 of tRNA_Asp. In
order to further characterize the activity of Dnmt2 we have used Drosophila Dnmt2 for
the identification of additional RNA targets.
In contrast to published results, we are able to observe in vitro methylating activity of
immunopurified Drosophila Dnmt2 enzyme and in vitro transcribed, unmodified
tRNA_Asp was recognized as a substrate. Furthermore, we identified Drosophila
tRNA_Val as a novel substrate for Dnmt2. Isolation of tRNA_Val out of wildtype and
mutant fly embryos shows an m5C-spot in 2-dimensional thin layer chromatography in
the wildtype tRNA_Val, which is absent in the mutant background. Specific cutting at
position C38 and quantification of the methylation signal was achieved by the application
of the sensitive DNAzyme technique. Our results demonstrate that tRNA methylation by
Dnmt2 is not limited to tRNA_Asp.
contact:
Dipl.-Biol. Madeleine Meusburger
German Cancer Research Center
German Cancer Research Center
M.Meusburger@dkfz-heidelberg.de
Im Neuenheimer Feld 580
69120 Heidelberg (Germany)
additional information
1_Division of Epigenetics, German Cancer Research Center, Im Neuenheimer Feld 580, 69120
Heidelberg, Germany
2_Department of Chemistry, Institute for Pharmacy and Molecular Biotechnology, University of
Heidelberg, Im Neuenheimer Feld 364; 69120 Heidelberg, Germany