RETRACTION
Volume 31, no. 17, p. 3515–3530, 2011, https://doi.org/10.1128/MCB.05424-11. We retract this article. We were recently made aware of an apparent duplication of panels in Fig. 2C and 4B, as well as an incorrect loading order in the top panel of Fig. 3C. Although these errors do not change the conclusions derived from these figures, we choose to retract this paper in the interest of maintaining accuracy in the published scientific literature. We apologize for these mistakes and any inconvenience they caused.