. "During interphase, cyclin B1 shuttles continuously in and out of the nucleus. The cyclin B cytoplasmic retention sequence (CRS), which is responsible for its interphase cytoplasmic localization, functions as a nuclear export sequence (Yang et al., 1998)."^^ . . . . . . . "Translocation of Cyclin B1:phospho-Cdc2 to the cytoplasm"^^ . . .