A role for cohesin in T-cell-receptor rearrangement and thymocyte differentiation by Seitan, VC, Hao, B, Tachibana-Konwalski, K, Lavagnolli, T, Mira-Bontenbal, H, Brown, K, Teng, G, Carroll, T, Terry, A, Horan, K, Marks, H, Adams, D, Schatz, D, Aragon, L, Fisher, A, Krangel, MS, Nasmyth, K, Merkenschlager, M