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AIR-2: An Aurora/Ipl1-related protein kinase associated with chromosomes and midbody microtubules is required for polar body extrusion and cytokinesis in Caenorhabditis elegans embryos.

Schumacher JM, Golden A, Donovan PJ - J. Cell Biol. (1998)

Bottom Line: Unlike other Aurora/Ipl1-related kinases, the Caenorhabditis elegans orthologue, AIR-2, is associated with meiotic and mitotic chromosomes.AIR-2 also remains associated with both extruded polar bodies.In the embryo, AIR-2 is found on metaphase chromosomes, moves to midbody microtubules at anaphase, and then persists at the cytokinesis remnant.

View Article: PubMed Central - PubMed

Affiliation: Cell Biology of Development and Differentiation Group, ABL-Basic Research Program, NCI-Frederick Cancer Research and Development Center, Frederick, Maryland 21702, USA.

ABSTRACT
An emerging family of kinases related to the Drosophila Aurora and budding yeast Ipl1 proteins has been implicated in chromosome segregation and mitotic spindle formation in a number of organisms. Unlike other Aurora/Ipl1-related kinases, the Caenorhabditis elegans orthologue, AIR-2, is associated with meiotic and mitotic chromosomes. AIR-2 is initially localized to the chromosomes of the most mature prophase I-arrested oocyte residing next to the spermatheca. This localization is dependent on the presence of sperm in the spermatheca. After fertilization, AIR-2 remains associated with chromosomes during each meiotic division. However, during both meiotic anaphases, AIR-2 is present between the separating chromosomes. AIR-2 also remains associated with both extruded polar bodies. In the embryo, AIR-2 is found on metaphase chromosomes, moves to midbody microtubules at anaphase, and then persists at the cytokinesis remnant. Disruption of AIR-2 expression by RNA- mediated interference produces entire broods of one-cell embryos that have executed multiple cell cycles in the complete absence of cytokinesis. The embryos accumulate large amounts of DNA and microtubule asters. Polar bodies are not extruded, but remain in the embryo where they continue to replicate. The cytokinesis defect appears to be late in the cell cycle because transient cleavage furrows initiate at the proper location, but regress before the division is complete. Additionally, staining with a marker of midbody microtubules revealed that at least some of the components of the midbody are not well localized in the absence of AIR-2 activity. Our results suggest that during each meiotic and mitotic division, AIR-2 may coordinate the congression of metaphase chromosomes with the subsequent events of polar body extrusion and cytokinesis.

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Specificity of the AIR-2 antibody. Western blots of protein lysates  from C. elegans embryos were prepared as  described in Materials and Methods. Affinity-purified AIR-2 antiserum specifically recognizes a protein of the predicted  size of 34.7 kD. Antibody recognition of  the 34.7-kD band is completely eliminated  by addition of the antigenic peptide to the  primary antibody incubation. α-Tubulin  was used as a protein loading control.
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Figure 2: Specificity of the AIR-2 antibody. Western blots of protein lysates from C. elegans embryos were prepared as described in Materials and Methods. Affinity-purified AIR-2 antiserum specifically recognizes a protein of the predicted size of 34.7 kD. Antibody recognition of the 34.7-kD band is completely eliminated by addition of the antigenic peptide to the primary antibody incubation. α-Tubulin was used as a protein loading control.

Mentions: To assess the location of the AIR-2 protein during C. elegans gametogenesis and early embryogenesis, a rabbit polyclonal antiserum was raised against a synthetic peptide corresponding to the COOH-terminal 12 amino acids of AIR-2. Western blot analysis of total protein lysates from C. elegans embryos probed with affinity-purified AIR-2 antisera revealed a single protein of the predicted size of 34.7 kD (Fig. 2). Antibody recognition of this protein was entirely competed by addition of the antigenic peptide to the primary antibody incubation (Fig. 2).


AIR-2: An Aurora/Ipl1-related protein kinase associated with chromosomes and midbody microtubules is required for polar body extrusion and cytokinesis in Caenorhabditis elegans embryos.

Schumacher JM, Golden A, Donovan PJ - J. Cell Biol. (1998)

Specificity of the AIR-2 antibody. Western blots of protein lysates  from C. elegans embryos were prepared as  described in Materials and Methods. Affinity-purified AIR-2 antiserum specifically recognizes a protein of the predicted  size of 34.7 kD. Antibody recognition of  the 34.7-kD band is completely eliminated  by addition of the antigenic peptide to the  primary antibody incubation. α-Tubulin  was used as a protein loading control.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2132979&req=5

Figure 2: Specificity of the AIR-2 antibody. Western blots of protein lysates from C. elegans embryos were prepared as described in Materials and Methods. Affinity-purified AIR-2 antiserum specifically recognizes a protein of the predicted size of 34.7 kD. Antibody recognition of the 34.7-kD band is completely eliminated by addition of the antigenic peptide to the primary antibody incubation. α-Tubulin was used as a protein loading control.
Mentions: To assess the location of the AIR-2 protein during C. elegans gametogenesis and early embryogenesis, a rabbit polyclonal antiserum was raised against a synthetic peptide corresponding to the COOH-terminal 12 amino acids of AIR-2. Western blot analysis of total protein lysates from C. elegans embryos probed with affinity-purified AIR-2 antisera revealed a single protein of the predicted size of 34.7 kD (Fig. 2). Antibody recognition of this protein was entirely competed by addition of the antigenic peptide to the primary antibody incubation (Fig. 2).

Bottom Line: Unlike other Aurora/Ipl1-related kinases, the Caenorhabditis elegans orthologue, AIR-2, is associated with meiotic and mitotic chromosomes.AIR-2 also remains associated with both extruded polar bodies.In the embryo, AIR-2 is found on metaphase chromosomes, moves to midbody microtubules at anaphase, and then persists at the cytokinesis remnant.

View Article: PubMed Central - PubMed

Affiliation: Cell Biology of Development and Differentiation Group, ABL-Basic Research Program, NCI-Frederick Cancer Research and Development Center, Frederick, Maryland 21702, USA.

ABSTRACT
An emerging family of kinases related to the Drosophila Aurora and budding yeast Ipl1 proteins has been implicated in chromosome segregation and mitotic spindle formation in a number of organisms. Unlike other Aurora/Ipl1-related kinases, the Caenorhabditis elegans orthologue, AIR-2, is associated with meiotic and mitotic chromosomes. AIR-2 is initially localized to the chromosomes of the most mature prophase I-arrested oocyte residing next to the spermatheca. This localization is dependent on the presence of sperm in the spermatheca. After fertilization, AIR-2 remains associated with chromosomes during each meiotic division. However, during both meiotic anaphases, AIR-2 is present between the separating chromosomes. AIR-2 also remains associated with both extruded polar bodies. In the embryo, AIR-2 is found on metaphase chromosomes, moves to midbody microtubules at anaphase, and then persists at the cytokinesis remnant. Disruption of AIR-2 expression by RNA- mediated interference produces entire broods of one-cell embryos that have executed multiple cell cycles in the complete absence of cytokinesis. The embryos accumulate large amounts of DNA and microtubule asters. Polar bodies are not extruded, but remain in the embryo where they continue to replicate. The cytokinesis defect appears to be late in the cell cycle because transient cleavage furrows initiate at the proper location, but regress before the division is complete. Additionally, staining with a marker of midbody microtubules revealed that at least some of the components of the midbody are not well localized in the absence of AIR-2 activity. Our results suggest that during each meiotic and mitotic division, AIR-2 may coordinate the congression of metaphase chromosomes with the subsequent events of polar body extrusion and cytokinesis.

Show MeSH
Related in: MedlinePlus