Studies on Ac/Ds methylation
--Lihua Wang, Manfred Heinlein and Peter Starlinger
In vitro, the DNA-binding affinity of the Ac transposase is enhanced if its hexameric target motif
AAACGG is hemimethylated. This observation by Reinhard Kunze seems to fit to the earlier finding by
geneticists that transposition is often linked to replication. In order to test the in vivo significance of
this correlation, we have begun genomic sequencing of the subterminal sequences of Ac by a PCR-based
method developed by Frommer et al. (PNAS 89:1827-1831, 1992). We make use of the fact that
the mutagen bisulfite is able to distinguish between methylated cytosin residues, which are stable, and
non-methylated cytosin residues, which are oxidatively desaminated to yield uracil.
Please Note: Notes submitted to the Maize Genetics Cooperation Newsletter may be cited only with consent of the authors
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