In vivo inhibition of cyclin B degradation and induction of cell-cycle arrest in mammalian cells by the neutral cysteine protease inhibitor N-acetylleucylleucylnorleucinal.
The cytotoxic neutral cysteine protease inhibitor N-acetylleucylleucylnorleucinal (ALLN) inhibits cell-cycle progression in CHO cells, affecting the G1/S and metaphase-anaphase transition points, as well as S phase. Mitotic arrest induced by ALLN is associated with the inhibition of cyclin B degradation. At mitosis-inhibiting concentrations of ALLN, cells undergo nuclear-envelope breakdown, spindle formation, chromosome condensation, and congression to the metaphase plate. However, normal anaphase events do not occur, and cells arrest in a metaphase configuration for a prolonged period. Steady-state levels of cyclin B increase to greater than normal mitotic levels, and cyclin B is not degraded for an extended period. Histone H1 kinase activity remains elevated during mitotic arrest. Duration of mitotic arrest depends on ALLN concentration; high concentrations (> 50 micrograms/ml) produce a prolonged mitotic arrest, whereas at lower concentrations, cells are transiently delayed through mitosis (up to 4-12 hr), after which they undergo aberrant cell division resulting in randomly sized daughter cells containing variable amounts of DNA. Cyclin B degradation fails to occur, and histone H1 kinase remains activated for the duration of mitotic arrest at all ALLN concentrations.
Department of Biological Sciences, Stanford University, CA 94305.
S W
SW
Sherwood
A L
AL
Kung
J
J
Roitelman
R D
RD
Simoni
R T
RT
Schimke
D000818:Animals; D016466:CHO Cells; D002453:Cell Cycle / Q000187:drug effects*; D006224:Cricetinae; D016213:Cyclins / Q000378:metabolism*; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology*; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D007700:Kinetics; D007976:Leupeptins / Q000494:pharmacology*; D008938:Mitosis / Q000187:drug effects; D006656:Protamine Kinase / Q000378:metabolism; D013997:Time Factors
D016213:Cyclins; D015853:Cysteine Proteinase Inhibitors; D007976:Leupeptins; C063261:acetylleucyl-leucyl-norleucinal; D006656:Protamine Kinase