Cell cycle dependent expression and stability of the nuclear protein detected by Ki-67 antibody in HL-60 cells

Cell Prolif. 1992 Jan;25(1):31-40. doi: 10.1111/j.1365-2184.1992.tb01435.x.


The expression and stability of the proliferation-associated nuclear antigen detected by Ki-67 antibody have been investigated in human promyelocytic leukaemic HL-60 cells in relation to their progression through the cell cycle. Expression of this antigen was minimal in late G1 and early S phase cells. The antigen accumulated in the cells predominantly during S phase, and its rate of increase per cell accelerated during the second half of this phase. The accumulation of Ki-67 antigen during S exceeded the increase in DNA content, and thus the Ki-67/DNA ratio rose 80% from late G1 to G2 + M. This antigen rapidly disappeared from post-mitotic cells. The half-life of this protein estimated in post-mitotic cells during stathmokinesis induced by vinblastine appeared to be shorter than 1 h. This rapid turnover should be compared with the relatively long (6-8 h) duration of G1 of the studied cells. In cells in which de novo protein synthesis was inhibited by 0.1 microgram/ml cycloheximide, the half-life of the Ki-67 antigen was also found to be about 1 h regardless of the cell position in the cell cycle. Thus, the data suggest that variations in the level of this protein during the cell cycle are a consequence of its different synthesis rate rather than phase-specific changes in the rate of its degradation. Because the late G1 and very early S phase cells express the antigen at levels only slightly above background, it is possible that, when using Ki-67 antibody as a marker of the cell growth fraction, some late G1 cells can be erroneously classified as non-cycling cells.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Antibodies
  • Cell Cycle / drug effects
  • Cell Cycle / genetics*
  • Cell Nucleus / metabolism*
  • Cycloheximide / pharmacology
  • DNA / analysis
  • Gene Expression
  • Humans
  • Ki-67 Antigen
  • Nuclear Proteins / biosynthesis*
  • Nuclear Proteins / immunology
  • Tumor Cells, Cultured / metabolism*
  • Tumor Cells, Cultured / pathology
  • Vinblastine / pharmacology


  • Antibodies
  • Ki-67 Antigen
  • Nuclear Proteins
  • Vinblastine
  • DNA
  • Cycloheximide