Section on Eukaryotic Transposable Elements, Laboratory of Gene Regulation and Development, National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892, USA.
In this issue of Molecular Cell, Dai et al. (2007) describe their exciting discovery that, in Saccharomyces cerevisiae, the integrase of retrotransposon Ty5 is phosphorylated, and this modification stabilizes the interaction between integrase and Sir4p that directs integration to heterochromatin.