Abstract
Chromosome segregation in mitosis is orchestrated by dynamic interaction between spindle microtubules and the kinetochore, a multiprotein complex assembled onto centromeric DNA of the chromosome. Here we show that Zwint-1 is required and is sufficient for kinetochore localization of Zeste White 10 (ZW10) in HeLa cells. Zwint-1 specifies the kinetochore association of ZW10 by interacting with its N-terminal domain. Suppression of synthesis of Zwint-1 by small interfering RNA abolishes the localization of ZW10 to the kinetochore, demonstrating the requirement of Zwint-1 for ZW10 kinetochore localization. In addition, depletion of Zwint-1 affects no mitotic arrest but causes aberrant premature chromosome segregation. These Zwint-1-suppressed cells display chromosome bridge phenotype with sister chromatids inter-connected. Moreover, Zwint-1 is required for stable association of CENP-F and dynamitin but not BUB1 with the kinetochore. Finally, our studies show that Zwint-1 is a new component of the mitotic check-point, as cells lacking Zwint-1 fail to arrest in mitosis when exposed to microtubule inhibitors, yielding interphase cells with multinuclei. As ZW10 and Zwint-1 are absent from yeast, we reasoned that metazoans evolved an elaborate spindle checkpoint machinery to ensure faithful chromosome segregation in mitosis.
Publication types
-
Research Support, Non-U.S. Gov't
MeSH terms
-
Animals
-
Binding Sites
-
Carrier Proteins / analysis
-
Carrier Proteins / genetics
-
Carrier Proteins / physiology*
-
Chromosomal Proteins, Non-Histone / analysis
-
Chromosomal Proteins, Non-Histone / genetics
-
Chromosomal Proteins, Non-Histone / metabolism*
-
Chromosome Segregation / physiology
-
Dynactin Complex
-
Gene Expression
-
Glutathione Transferase / genetics
-
Green Fluorescent Proteins / genetics
-
HeLa Cells
-
Humans
-
Intracellular Signaling Peptides and Proteins
-
Kinetochores / chemistry
-
Kinetochores / metabolism*
-
Mice
-
Mice, Inbred BALB C
-
Microfilament Proteins
-
Microtubule-Associated Proteins / analysis
-
Microtubule-Associated Proteins / genetics
-
Microtubule-Associated Proteins / metabolism*
-
Mitosis / physiology*
-
Nuclear Proteins
-
Peptide Fragments / metabolism
-
RNA, Small Interfering / genetics
-
RNA, Small Interfering / physiology
-
Recombinant Fusion Proteins
-
Signal Transduction / physiology*
-
Transfection
Substances
-
Carrier Proteins
-
Chromosomal Proteins, Non-Histone
-
DCTN2 protein, human
-
Dctn2 protein, mouse
-
Dynactin Complex
-
Intracellular Signaling Peptides and Proteins
-
Microfilament Proteins
-
Microtubule-Associated Proteins
-
Nuclear Proteins
-
Peptide Fragments
-
RNA, Small Interfering
-
Recombinant Fusion Proteins
-
ZW10 protein, human
-
ZWINT protein, human
-
centromere protein F
-
green fluorescent protein, Aequorea victoria
-
Green Fluorescent Proteins
-
Glutathione Transferase