CD74 downstream signaling cascade induces cyclin E expression. (A-B) Cyclin E expression. IgD⁺ B cells from control mice were stimulated with anti-CD74 antibody or nonspecific anti-CD8 antibody for various time periods. (A) Total RNA was isolated, and reverse transcription was carried out using Superscript II RT. (B) Cells were lysed, and lysates were separated on SDS-PAGE and blotted with anti–cyclin E or antitubulin antibodies.