YB-1 as a cell cycle-regulated transcription factor facilitating cyclin A and cyclin B1 gene expression


  • K. Juerchott
  • S. Bergmann
  • U. Stein
  • W. Walther
  • M. Janz
  • I. Manni
  • G. Piaggio
  • E. Fietze
  • M. Dietel
  • H.D. Royer


  • Journal of Biological Chemistry


  • J Biol Chem 278 (30): 27988-27996


  • Expression of the Y-box protein YB-1 is increased in proliferating normal and cancer cells, but its role in cell proliferation and cell cycle progression is unclear. We have identified a cell cycle-dependent relocalization of YB-1 from the cytoplasm to the nucleus at the G1/S phase transition and demonstrate that both the charged zipper and the cold shock domain are involved in regulating this process. Using cell lines that constitutively overexpress YB-1, we show that nuclear accumulation of YB-1 is associated with increased cyclin A and cyclin B1 mRNA and protein expression. We provide evidence that deregulated YB-1 expression is linked to adhesion-independent cell proliferation through the induction of cyclin A. Thus, we have identified YB-1 as a cell cycle stage-specific transcription factor important for cell proliferation.