Predominant cytoplasmic localization of the AID protein in BL and DLBCL. Nuclear (N) and cytoplasmic (C) fractions were prepared from 10 AID-positive lymphoma cell lines, including 3 BL and 7 DLBCL, and immunoblotted with anti-AID Abs, followed by anti-BCL6 (nuclear) and anti-α-tubulin (cytoplasmic) as controls for the purity of the fractions. The presence or absence of ASHM is also given; nd indicates not determined.