Lh. Wang et R. Kunze, TRANSPOSASE BINDING-SITE METHYLATION IN THE EPIGENETICALLY INACTIVATED AC DERIVATIVE DS-CY, Plant journal, 13(4), 1998, pp. 577-582
The authors have determined the C-methylation pattern of the non-auton
omous transposable element Ds-cy, which is an epigenetically inactivat
ed, transcriptionally silent derivative of the maize Activator (Ac) el
ement. Like Ac, Ds-cy is hypermethylated at the 3'-end. However, in Ds
-cy the 5'-end is also hypermethylated, including all subterminal bind
ing sites for the Ac-encoded transposase protein. As Ds-cy transposes
in the presence of an active Ac in the genome, the authors conclude th
at methylation of the 5'-end TPase binding sites does not interfere wi
th transposition, but correlates with inactivity of the Ac promoter. T
he authors discuss the implications of these results for the chromatid
selectivity of Ac/Ds transposition and the mechanism of Ac-induced ch
romosome breakage events.