Making ends meet in class switch recombination

Liu et al. revealed that ERCC6L2 is a DNA double strand break repair factor that both enhances the efficiency of immunoglobulin gene class switch recombination and dictates the proper orientation of end joining. ERCC6L2 rapidly localizes to DNA breaks and is necessary for efficient recruitment of other repair factors, suggesting an integral and early role in the complex process that allows for the expression of antibodies with different effector functions.