The selective continued linkage of centromeres from mitosis to interphase in the absence of mammalian separase.
Separase is an evolutionarily conserved protease that is essential for chromosome segregation and cleaves cohesin Scc1/Rad21, which joins the sister chromatids together. Although mammalian separase also functions in chromosome segregation, our understanding of this process in mammals is still incomplete. We generated separase knockout mice, reporting an essential function for mammalian separase. Separase-deficient mouse embryonic fibroblasts exhibited severely restrained increases in cell number, polyploid chromosomes, and amplified centrosomes. Chromosome spreads demonstrated that multiple chromosomes connected to a centromeric region. Live observation demonstrated that the chromosomes of separase-deficient cells condensed, but failed to segregate, although subsequent cytokinesis and chromosome decondensation proceeded normally. These results establish that mammalian separase is essential for the separation of centromeres, but not of the arm regions of chromosomes. Other cell cycle events, such as mitotic exit, DNA replication, and centrosome duplication appear to occur normally. We also demonstrated that heterozygous separase-deficient cells exhibited severely restrained increases in cell number with apparently normal mitosis in the absence of securin, which is an inhibitory partner of separase.
Japanese Foundation for Cancer Research, Cancer Institute, Tokyo 135-8550, Japan.
Kazuki
K
Kumada
Ryoji
R
Yao
Tokuichi
T
Kawaguchi
Mika
M
Karasawa
Yutaka
Y
Hoshikawa
Koji
K
Ichikawa
Yoshinobu
Y
Sugitani
Issei
I
Imoto
Johji
J
Inazawa
Minoru
M
Sugawara
Mitsuhiro
M
Yanagida
Tetsuo
T
Noda
D000818:Animals; D002352:Carrier Proteins / Q000235:genetics; D018797:Cell Cycle Proteins / Q000235:genetics*; D049109:Cell Proliferation; D002478:Cells, Cultured; D002503:Centromere / Q000502:physiology*; D018385:Centrosome / Q000502:physiology; D020090:Chromosome Segregation / Q000502:physiology*; D048749:Cytokinesis / Q000502:physiology; D010450:Endopeptidases / Q000235:genetics*; D005260:Female; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism*; D007399:Interphase / Q000502:physiology*; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D008938:Mitosis / Q000502:physiology*; D011123:Polyploidy; D064249:Securin; D064247:Separase
D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D064249:Securin; D010450:Endopeptidases; D064247:Separase