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Dynein is a transient kinetochore component whose binding is regulated by microtubule attachment, not tension.

King JM, Hays TS, Nicklas RB - J. Cell Biol. (2000)

Bottom Line: We have determined that these differences in staining intensity reflect differences in amounts of dynein associated with the kinetochore.As a result, the bulk of the dynein leaves the kinetochore very early in mitosis, soon after the kinetochores begin to attach to microtubules.The possible functions of this dynein fraction are therefore limited to the initial attachment and movement of chromosomes and/or to a role in the mitotic checkpoint.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, Duke University, Durham, North Carolina 27708, USA.

ABSTRACT
Cytoplasmic dynein is the only known kinetochore protein capable of driving chromosome movement toward spindle poles. In grasshopper spermatocytes, dynein immunofluorescence staining is bright at prometaphase kinetochores and dimmer at metaphase kinetochores. We have determined that these differences in staining intensity reflect differences in amounts of dynein associated with the kinetochore. Metaphase kinetochores regain bright dynein staining if they are detached from spindle microtubules by micromanipulation and kept detached for 10 min. We show that this increase in dynein staining is not caused by the retraction or unmasking of dynein upon detachment. Thus, dynein genuinely is a transient component of spermatocyte kinetochores. We further show that microtubule attachment, not tension, regulates dynein localization at kinetochores. Dynein binding is extremely sensitive to the presence of microtubules: fewer than half the normal number of kinetochore microtubules leads to the loss of most kinetochoric dynein. As a result, the bulk of the dynein leaves the kinetochore very early in mitosis, soon after the kinetochores begin to attach to microtubules. The possible functions of this dynein fraction are therefore limited to the initial attachment and movement of chromosomes and/or to a role in the mitotic checkpoint.

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Specificity of the mouse monoclonal antidynein heavy chain antibody P1H4: lanes 1 and 2, Coomassie blue–stained gel of fly testis and grasshopper testis homogenates, respectively; lanes 3 and 4, duplicate gel blotted and probed with the P1H4 monoclonal antibody. The P1H4 specifically detects dynein heavy chain (arrowhead) in both fly and grasshopper testis. Molecular mass values are indicated to the left of lane 1.
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Figure 1: Specificity of the mouse monoclonal antidynein heavy chain antibody P1H4: lanes 1 and 2, Coomassie blue–stained gel of fly testis and grasshopper testis homogenates, respectively; lanes 3 and 4, duplicate gel blotted and probed with the P1H4 monoclonal antibody. The P1H4 specifically detects dynein heavy chain (arrowhead) in both fly and grasshopper testis. Molecular mass values are indicated to the left of lane 1.

Mentions: The P1H4 antibody is a monoclonal antibody that specifically recognizes Drosophila cytoplasmic dynein heavy chain (McGrail and Hays 1997). When probed against grasshopper testis, the antibody recognizes one band with the same molecular mass as Drosophila dynein heavy chain (Fig. 1). Thus, the P1H4 antibody specifically recognizes dynein heavy chain in grasshopper spermatocytes.


Dynein is a transient kinetochore component whose binding is regulated by microtubule attachment, not tension.

King JM, Hays TS, Nicklas RB - J. Cell Biol. (2000)

Specificity of the mouse monoclonal antidynein heavy chain antibody P1H4: lanes 1 and 2, Coomassie blue–stained gel of fly testis and grasshopper testis homogenates, respectively; lanes 3 and 4, duplicate gel blotted and probed with the P1H4 monoclonal antibody. The P1H4 specifically detects dynein heavy chain (arrowhead) in both fly and grasshopper testis. Molecular mass values are indicated to the left of lane 1.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2169441&req=5

Figure 1: Specificity of the mouse monoclonal antidynein heavy chain antibody P1H4: lanes 1 and 2, Coomassie blue–stained gel of fly testis and grasshopper testis homogenates, respectively; lanes 3 and 4, duplicate gel blotted and probed with the P1H4 monoclonal antibody. The P1H4 specifically detects dynein heavy chain (arrowhead) in both fly and grasshopper testis. Molecular mass values are indicated to the left of lane 1.
Mentions: The P1H4 antibody is a monoclonal antibody that specifically recognizes Drosophila cytoplasmic dynein heavy chain (McGrail and Hays 1997). When probed against grasshopper testis, the antibody recognizes one band with the same molecular mass as Drosophila dynein heavy chain (Fig. 1). Thus, the P1H4 antibody specifically recognizes dynein heavy chain in grasshopper spermatocytes.

Bottom Line: We have determined that these differences in staining intensity reflect differences in amounts of dynein associated with the kinetochore.As a result, the bulk of the dynein leaves the kinetochore very early in mitosis, soon after the kinetochores begin to attach to microtubules.The possible functions of this dynein fraction are therefore limited to the initial attachment and movement of chromosomes and/or to a role in the mitotic checkpoint.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, Duke University, Durham, North Carolina 27708, USA.

ABSTRACT
Cytoplasmic dynein is the only known kinetochore protein capable of driving chromosome movement toward spindle poles. In grasshopper spermatocytes, dynein immunofluorescence staining is bright at prometaphase kinetochores and dimmer at metaphase kinetochores. We have determined that these differences in staining intensity reflect differences in amounts of dynein associated with the kinetochore. Metaphase kinetochores regain bright dynein staining if they are detached from spindle microtubules by micromanipulation and kept detached for 10 min. We show that this increase in dynein staining is not caused by the retraction or unmasking of dynein upon detachment. Thus, dynein genuinely is a transient component of spermatocyte kinetochores. We further show that microtubule attachment, not tension, regulates dynein localization at kinetochores. Dynein binding is extremely sensitive to the presence of microtubules: fewer than half the normal number of kinetochore microtubules leads to the loss of most kinetochoric dynein. As a result, the bulk of the dynein leaves the kinetochore very early in mitosis, soon after the kinetochores begin to attach to microtubules. The possible functions of this dynein fraction are therefore limited to the initial attachment and movement of chromosomes and/or to a role in the mitotic checkpoint.

Show MeSH
Related in: MedlinePlus