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The microtubule-dependent motor centromere-associated protein E (CENP-E) is an integral component of kinetochore corona fibers that link centromeres to spindle microtubules.

Yao X, Anderson KL, Cleveland DW - J. Cell Biol. (1997)

Bottom Line: Centromere-associated protein E (CENP-E) is a kinesin-related microtubule motor protein that is essential for chromosome congression during mitosis.In congressing chromosomes, CENP-E is preferentially associated with (or accessible at) the stretched, leading kinetochore known to provide the primary power for chromosome movement.Taken together, this evidence strongly supports a model in which CENP-E functions in congression to tether kinetochores to the disassembling microtubule plus ends.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Cell Biology, Ludwig Institute for Cancer Research, School of Medicine, University of California, La Jolla, CA 92093-0660, USA.

ABSTRACT
Centromere-associated protein E (CENP-E) is a kinesin-related microtubule motor protein that is essential for chromosome congression during mitosis. Using immunoelectron microscopy, CENP-E is shown to be an integral component of the kinetochore corona fibers that tether centromeres to the spindle. Immediately upon nuclear envelope fragmentation, an associated plus end motor trafficks cytoplasmic CENP-E toward chromosomes along astral microtubules that enter the nuclear volume. Before or concurrently with initial lateral attachment of spindle microtubules, CENP-E targets to the outermost region of the developing kinetochores. After stable attachment, throughout chromosome congression, at metaphase, and throughout anaphase A, CENP-E is a constituent of the corona fibers, extending at least 50 nm away from the kinetochore outer plate and intertwining with spindle microtubules. In congressing chromosomes, CENP-E is preferentially associated with (or accessible at) the stretched, leading kinetochore known to provide the primary power for chromosome movement. Taken together, this evidence strongly supports a model in which CENP-E functions in congression to tether kinetochores to the disassembling microtubule plus ends.

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At early prometaphase, CENP-E binds all  long the outermost surface of  monooriented kinetochores  attached laterally to spindle  microtubules. HeLa cells  grown on coverslips were  preextracted and fixed. The  visualization of CENP-E was  achieved by 10-nm gold–conjugated goat anti–rabbit IgG.  (A, C, and E) Low magnification serial sections of an early  prometaphase HeLa cell. Asterisks denote the two poles  of the developing bipolar  spindle. An apparently monooriented chromosome is  boxed, and higher power  views are shown in B, D, and  F. 10-nm gold particles representing CENP-E position  decorate the interface between immature kinetochore  and the laterally attached  spindle microtubules. Note  the labeling of CENP-E on  the kinetochore appears as a  crescent (C) shape. Bars: (A,  C, and E) 2 μm; (B) 160 nm;  (D and F) 110 nm.
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Figure 3: At early prometaphase, CENP-E binds all long the outermost surface of monooriented kinetochores attached laterally to spindle microtubules. HeLa cells grown on coverslips were preextracted and fixed. The visualization of CENP-E was achieved by 10-nm gold–conjugated goat anti–rabbit IgG. (A, C, and E) Low magnification serial sections of an early prometaphase HeLa cell. Asterisks denote the two poles of the developing bipolar spindle. An apparently monooriented chromosome is boxed, and higher power views are shown in B, D, and F. 10-nm gold particles representing CENP-E position decorate the interface between immature kinetochore and the laterally attached spindle microtubules. Note the labeling of CENP-E on the kinetochore appears as a crescent (C) shape. Bars: (A, C, and E) 2 μm; (B) 160 nm; (D and F) 110 nm.

Mentions: Serial micrographs (Fig. 3, A, C, and E) from cells in prometaphase revealed numerous apparently monoorientated chromosomes attached laterally to spindle microtubules. At higher magnification of one telocentric chromosome pair (Fig. 3, B, D, and F), the gold particles marking CENP-E position were seen at the interfaces of the developing kinetochores with their laterally associated spindle microtubules (Fig. 3, B, D, and F), with virtually no gold found on other microtubules or at the surface regions of the chromosome. While we cannot be absolutely certain in this example that all of the microtubules are from the adjacent pole, it is likely that these chromosomes are monooriented. Moreover, it is clear that in this example and in 13 other cells examined, CENP-E is found in a fibrous network extending 30–60 nm from the not fully developed outer kinetochore surfaces of the sister kinetochores. In addition, CENP-E surrounds the semicircular, immature kinetochores, both those with obvious lateral attachment to microtubules and without associated microtubules. These findings demonstrate that at the earliest stages of microtubule–chromosome interaction, CENP-E is highly concentrated at the surface of the centromere as a fibrillar component extending up to 60 nm. Thus, the prometaphase kinetochore outermost surface is surrounded by a collar of CENP-E molecules.


The microtubule-dependent motor centromere-associated protein E (CENP-E) is an integral component of kinetochore corona fibers that link centromeres to spindle microtubules.

Yao X, Anderson KL, Cleveland DW - J. Cell Biol. (1997)

At early prometaphase, CENP-E binds all  long the outermost surface of  monooriented kinetochores  attached laterally to spindle  microtubules. HeLa cells  grown on coverslips were  preextracted and fixed. The  visualization of CENP-E was  achieved by 10-nm gold–conjugated goat anti–rabbit IgG.  (A, C, and E) Low magnification serial sections of an early  prometaphase HeLa cell. Asterisks denote the two poles  of the developing bipolar  spindle. An apparently monooriented chromosome is  boxed, and higher power  views are shown in B, D, and  F. 10-nm gold particles representing CENP-E position  decorate the interface between immature kinetochore  and the laterally attached  spindle microtubules. Note  the labeling of CENP-E on  the kinetochore appears as a  crescent (C) shape. Bars: (A,  C, and E) 2 μm; (B) 160 nm;  (D and F) 110 nm.
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getmorefigures.php?uid=PMC2139792&req=5

Figure 3: At early prometaphase, CENP-E binds all long the outermost surface of monooriented kinetochores attached laterally to spindle microtubules. HeLa cells grown on coverslips were preextracted and fixed. The visualization of CENP-E was achieved by 10-nm gold–conjugated goat anti–rabbit IgG. (A, C, and E) Low magnification serial sections of an early prometaphase HeLa cell. Asterisks denote the two poles of the developing bipolar spindle. An apparently monooriented chromosome is boxed, and higher power views are shown in B, D, and F. 10-nm gold particles representing CENP-E position decorate the interface between immature kinetochore and the laterally attached spindle microtubules. Note the labeling of CENP-E on the kinetochore appears as a crescent (C) shape. Bars: (A, C, and E) 2 μm; (B) 160 nm; (D and F) 110 nm.
Mentions: Serial micrographs (Fig. 3, A, C, and E) from cells in prometaphase revealed numerous apparently monoorientated chromosomes attached laterally to spindle microtubules. At higher magnification of one telocentric chromosome pair (Fig. 3, B, D, and F), the gold particles marking CENP-E position were seen at the interfaces of the developing kinetochores with their laterally associated spindle microtubules (Fig. 3, B, D, and F), with virtually no gold found on other microtubules or at the surface regions of the chromosome. While we cannot be absolutely certain in this example that all of the microtubules are from the adjacent pole, it is likely that these chromosomes are monooriented. Moreover, it is clear that in this example and in 13 other cells examined, CENP-E is found in a fibrous network extending 30–60 nm from the not fully developed outer kinetochore surfaces of the sister kinetochores. In addition, CENP-E surrounds the semicircular, immature kinetochores, both those with obvious lateral attachment to microtubules and without associated microtubules. These findings demonstrate that at the earliest stages of microtubule–chromosome interaction, CENP-E is highly concentrated at the surface of the centromere as a fibrillar component extending up to 60 nm. Thus, the prometaphase kinetochore outermost surface is surrounded by a collar of CENP-E molecules.

Bottom Line: Centromere-associated protein E (CENP-E) is a kinesin-related microtubule motor protein that is essential for chromosome congression during mitosis.In congressing chromosomes, CENP-E is preferentially associated with (or accessible at) the stretched, leading kinetochore known to provide the primary power for chromosome movement.Taken together, this evidence strongly supports a model in which CENP-E functions in congression to tether kinetochores to the disassembling microtubule plus ends.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Cell Biology, Ludwig Institute for Cancer Research, School of Medicine, University of California, La Jolla, CA 92093-0660, USA.

ABSTRACT
Centromere-associated protein E (CENP-E) is a kinesin-related microtubule motor protein that is essential for chromosome congression during mitosis. Using immunoelectron microscopy, CENP-E is shown to be an integral component of the kinetochore corona fibers that tether centromeres to the spindle. Immediately upon nuclear envelope fragmentation, an associated plus end motor trafficks cytoplasmic CENP-E toward chromosomes along astral microtubules that enter the nuclear volume. Before or concurrently with initial lateral attachment of spindle microtubules, CENP-E targets to the outermost region of the developing kinetochores. After stable attachment, throughout chromosome congression, at metaphase, and throughout anaphase A, CENP-E is a constituent of the corona fibers, extending at least 50 nm away from the kinetochore outer plate and intertwining with spindle microtubules. In congressing chromosomes, CENP-E is preferentially associated with (or accessible at) the stretched, leading kinetochore known to provide the primary power for chromosome movement. Taken together, this evidence strongly supports a model in which CENP-E functions in congression to tether kinetochores to the disassembling microtubule plus ends.

Show MeSH
Related in: MedlinePlus