Introducing the mighty panoramix: Defender of genomes

Organisms from bacteria to humans must defend themselves against parasitic genetic elements called transposons, and the stakes are high.

These pieces of DNA, which disrupt genes by jumping around in the genome, can cause so much destruction that cells have dedicated surveillance mechanisms to keep them in check.

To protect future generations against genomic havoc, defects in these innate defense systems usually result in sterility. In animals, the main defense against troublemaking transposons is the Piwi-interacting RNA pathway.

The Piwi-interacting RNA pathway, which is active in germline cells -- those that give rise to sperm and eggs -- is a double-tiered defense system. The most direct line of defense finds and chews up RNA copies of transposons, while a second mechanism finds transposons within the genome and tags them with chemical signals that instruct the cell to keep them safely off.

In new research, scientists led by Cold Spring Harbor Laboratory (CSHL) Professor Gregory Hannon, who is also a Professor and Senior Group Leader at the CRUK Cambridge Institute at the University of Cambridge, have identified a protein the Piwi system uses to guide a cell's gene-silencing machinery to the right spots in the genome, allowing it to keep transposons inactive without interfering with the organism's own genes.

Hannon's colleagues have playfully named the protein Panoramix, after a comic book character who endows others with great power.