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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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CENP-E remains  a component of the kinetochore fibers as sister chromatids move toward the poles in  anaphase. HeLa cells were  processed as described in Fig.  2. (A) Low magnification  view of an early anaphase  HeLa cell. The two spindle  pole positions are marked  with asterisks (one is apparent  while another is in a different  section). (B) Magnified view  of a kinetochore–microtubule  interface shows that CENP-E  is located between the kinetochore outer plate and the  spindle microtubules (arrow). No gold particles are  seen in other regions on  chromosomes or on microtubules. (C) Low magnification  view of a late anaphase HeLa  cell bearing elongated spindle poles, labeled with asterisks; one is apparent while  another is in a different section. Interzonal microtubules  are readily seen (arrow). (D)  Magnified view of the upper  boxed region in C, showing  that CENP-E is located between a kinetochore and its  associated spindle microtubules (arrow). Examination  of the number of particles revealed a reduction relative to  metaphase. (E) Magnified  view of area pointed by the  arrow in C. Some CENP-E is  now localized to the interzonal microtubules. Bars:  (A) 2 μm; (B) 120 nm; (C)  2 μm; (D) 70 nm; (E) 90 nm.
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Figure 7: CENP-E remains a component of the kinetochore fibers as sister chromatids move toward the poles in anaphase. HeLa cells were processed as described in Fig. 2. (A) Low magnification view of an early anaphase HeLa cell. The two spindle pole positions are marked with asterisks (one is apparent while another is in a different section). (B) Magnified view of a kinetochore–microtubule interface shows that CENP-E is located between the kinetochore outer plate and the spindle microtubules (arrow). No gold particles are seen in other regions on chromosomes or on microtubules. (C) Low magnification view of a late anaphase HeLa cell bearing elongated spindle poles, labeled with asterisks; one is apparent while another is in a different section. Interzonal microtubules are readily seen (arrow). (D) Magnified view of the upper boxed region in C, showing that CENP-E is located between a kinetochore and its associated spindle microtubules (arrow). Examination of the number of particles revealed a reduction relative to metaphase. (E) Magnified view of area pointed by the arrow in C. Some CENP-E is now localized to the interzonal microtubules. Bars: (A) 2 μm; (B) 120 nm; (C) 2 μm; (D) 70 nm; (E) 90 nm.

Mentions: To verify if CENP-E is located in the kinetochore corona during anaphase chromosome movement toward the poles, CENP-E positioning was examined in cells early in anaphase (anaphase A; Fig. 7, A and B). The deposition of gold particles demonstrated that CENP-E remains a kinetochore corona component, extending along spindle microtubules (Fig. 7 B, arrow). Later in anaphase, when chromosomes have moved most of the way to the poles and pole separation has been initiated (anaphase B), CENP-E is still localized to the kinetochore outer plate (Fig. 7 C, boxed area, D, arrows), but a significant number of gold particles are now found redistributed to the interzonal microtubules (Fig. 7 C, arrow; E). Examination of 32 anaphase kinetochore sections (from both randomly picked and serial stacks) revealed that the number of gold particles located to kinetochores is reduced by about half compared with metaphase chromosomes (8 ± 3 for metaphase vs 5 ± 2 for anaphase). Again, very few gold particles were found elsewhere in the cytoplasm.


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)

CENP-E remains  a component of the kinetochore fibers as sister chromatids move toward the poles in  anaphase. HeLa cells were  processed as described in Fig.  2. (A) Low magnification  view of an early anaphase  HeLa cell. The two spindle  pole positions are marked  with asterisks (one is apparent  while another is in a different  section). (B) Magnified view  of a kinetochore–microtubule  interface shows that CENP-E  is located between the kinetochore outer plate and the  spindle microtubules (arrow). No gold particles are  seen in other regions on  chromosomes or on microtubules. (C) Low magnification  view of a late anaphase HeLa  cell bearing elongated spindle poles, labeled with asterisks; one is apparent while  another is in a different section. Interzonal microtubules  are readily seen (arrow). (D)  Magnified view of the upper  boxed region in C, showing  that CENP-E is located between a kinetochore and its  associated spindle microtubules (arrow). Examination  of the number of particles revealed a reduction relative to  metaphase. (E) Magnified  view of area pointed by the  arrow in C. Some CENP-E is  now localized to the interzonal microtubules. Bars:  (A) 2 μm; (B) 120 nm; (C)  2 μm; (D) 70 nm; (E) 90 nm.
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Related In: Results  -  Collection

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Figure 7: CENP-E remains a component of the kinetochore fibers as sister chromatids move toward the poles in anaphase. HeLa cells were processed as described in Fig. 2. (A) Low magnification view of an early anaphase HeLa cell. The two spindle pole positions are marked with asterisks (one is apparent while another is in a different section). (B) Magnified view of a kinetochore–microtubule interface shows that CENP-E is located between the kinetochore outer plate and the spindle microtubules (arrow). No gold particles are seen in other regions on chromosomes or on microtubules. (C) Low magnification view of a late anaphase HeLa cell bearing elongated spindle poles, labeled with asterisks; one is apparent while another is in a different section. Interzonal microtubules are readily seen (arrow). (D) Magnified view of the upper boxed region in C, showing that CENP-E is located between a kinetochore and its associated spindle microtubules (arrow). Examination of the number of particles revealed a reduction relative to metaphase. (E) Magnified view of area pointed by the arrow in C. Some CENP-E is now localized to the interzonal microtubules. Bars: (A) 2 μm; (B) 120 nm; (C) 2 μm; (D) 70 nm; (E) 90 nm.
Mentions: To verify if CENP-E is located in the kinetochore corona during anaphase chromosome movement toward the poles, CENP-E positioning was examined in cells early in anaphase (anaphase A; Fig. 7, A and B). The deposition of gold particles demonstrated that CENP-E remains a kinetochore corona component, extending along spindle microtubules (Fig. 7 B, arrow). Later in anaphase, when chromosomes have moved most of the way to the poles and pole separation has been initiated (anaphase B), CENP-E is still localized to the kinetochore outer plate (Fig. 7 C, boxed area, D, arrows), but a significant number of gold particles are now found redistributed to the interzonal microtubules (Fig. 7 C, arrow; E). Examination of 32 anaphase kinetochore sections (from both randomly picked and serial stacks) revealed that the number of gold particles located to kinetochores is reduced by about half compared with metaphase chromosomes (8 ± 3 for metaphase vs 5 ± 2 for anaphase). Again, very few gold particles were found elsewhere in the cytoplasm.

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