In Science this week, a team from the University of Cambridge reports the discovery of a new player in the DNA double-strand break (DSB) repair process. The researchers identified human PAXX, a paralog of XRCC4 and XLF — two structurally related proteins that participate in DSB repair — as a new XRCC4 superfamily member that interacts directly with the DSB repair protein Ku and that is recruited to cellular DNA-damage sites. The researchers also show that PAXX works with XRCC4 and XLF to mediate DSB repair and cell survival in response to DSB-inducing agents and report that it is involved in the assembly of factors required for another DNA repair pathway, nonhomologous end-joining.
Also in Science, three experts sound off on the recent European Commission Scientific Committee's issuance of a draft opinion on risk assessment methods for synthetic biology. In an editorial, University of Manchester's Rainer Breitling and Eriko Takano, along with Riffyn CEO Timothy Gardner, note that the committee recommended standardizing and streamlining the process by which genetic engineering information is submitted to risk assessors. It also suggested the use of genetically modified organisms with a record of safety as comparator organisms and highlight the importance of being able to predict the behavior of complex engineered organisms. The committee also stated that existing genetic safety mechanisms are insufficient to address the risks of synthetic biology. Given the impact the committee's opinion will have, the Breitling, Takano, and Gardner urge the scientific community to comment on the draft opinion before a final opinion is issued this spring.