Actin-binding proteins required for reliable chromosome segregation in mitosis.
While studying mitosis in Dictyostelium mutants with deficiencies in actin-binding proteins, we found that two of these proteins, cortexillin and Aip1, are required for the precise segregation of chromosomes. Atypical spindles and nuclei with varying DNA content indicate that mutants lacking cortexillin or Aip1 are genetically unstable. These aberrations are caused by the detachment and irregular reattachment of centrosomes to the nuclear surface. Live imaging showed how coalescing mitotic complexes give rise to a multipolar spindle, and how excess centrosomes can be eliminated by mitotic cleavage between anucleate and nucleated portions of a cell. We hypothesize that mutations in regulatory proteins of the actin network might be one cause of genetic instability of malignant tumor cells.
Gerisch
Günther
G
Max-Planck-Institut für Biochemie, Martinsried, Germany. gerisch@biochem.mpg.de
Faix
Jan
J
Köhler
Jana
J
Müller-Taubenberger
Annette
A
D008841:Actin Cytoskeleton / Q000235:genetics / Q000378:metabolism; D000818:Animals; D002869:Chromosome Aberrations; D020090:Chromosome Segregation / Q000235:genetics*; D004023:Dictyostelium / Q000235:genetics* / Q000378:metabolism*; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics; D008840:Microfilament Proteins / Q000378:metabolism*; D008938:Mitosis / Q000235:genetics*; D015800:Protozoan Proteins / Q000378:metabolism; D008941:Spindle Apparatus / Q000502:physiology / Q000648:ultrastructure
D008840:Microfilament Proteins; D015800:Protozoan Proteins