BAF goes nuclear

Barrier-to-autointegration factor (BAF) was first described as a cellular activity that prevents retroviral DNA from undergoing suicidal autointegration, but its function in uninfected cells remained obscure. Segura-Totten et al. (page 475) have now performed a detailed biochemical characterization of BAF. The work defines critical functional motifs of this DNA-bridging protein, and suggests that BAF is essential for chromatin decondensation and nuclear envelope assembly and growth.

Previous work had shown that BAF binds to DNA and to proteins containing a LEM domain, a structure that defines a family of nuclear membrane proteins. Using biochemical assays and a panel of site-directed mutants, the authors identified residues of BAF required for the protein to bind to itself, to DNA, and to emerin, a LEM-containing protein. Adding a low concentration of wild-type...