Silencing “Selfish DNA” — Transposable elements (TEs) are mobile segments of genomic DNA that are often referred to as “selfish DNA” because they insert copies of themselves into different locations within the genome where they can cause harmful mutations. For this reason, it is important that cells repress TEs. A collaborative study between the laboratories of Drs. Arthur Skoultchi and Dmitry Fyodorov, published in the April 5 issue of Science, has revealed a novel mechanism for TE silencing that appears to protect chromosomes from injury. The current model highlights small RNA interference as the major pathway for TE repression; however, the Einstein team, including first author Dr. Xingwu Lu, discovered a new pathway, which silences TEs by compacting the regions of the genome in which they are located, effectively inactivating the selfish DNA. The researchers also show that the linker histone H1 specifically recruits a “code-writer” enzyme, Su(var)3-9, which marks the TEs for silencing. Dr. Skoultchi is professor and chair of cell biology, as well as the Judith and Burton P. Resnick Chair in Cell Biology; Dr. Fyodorov is associate professor and Dr. Lu is an associate in the same department.
Posted on: Monday, May 13, 2013