Studying DNA repair and protein modification

Homologous recombination is an important mechanism for the repair of damaged chromosomes. When this occurs, a Displacement Loop, or "D-loop," is formed as the two strands of the DNA molecule are separated and held apart by a third strand of DNA. Patrick Sung's laboratory at Yale University has detailed a method for generating these structures in their article, "Assay for Human Rad51-Mediated DNA Displacement Loop Formation." This reconstituted system provides researchers a biochemical means to dissect the mechanisms of the homologous recombination machinery.

Sumoylation involves the attachment of Small Ubiquitin-like Modifier or "SUMO" proteins to other proteins in a cell. Sumoylation modifies these target proteins and can affect a variety of activities, including stability, transport, and transcriptional regulation. James Manley's laboratory at Columbia University provides "In Vitro Sumoylation of Recombinant Proteins and Subsequent Purification for Use in Enzymatic Assays," a protocol for modifying proteins in this manner, allowing one to assess the impact of sumoylation. This method is freely accessible on the website for Cold Spring Harbor Protocols (www.cshprotocols.org/cgi/content/full/2009/1/pdb.prot5121).