Each cell in the human body contains 46 different chromosomes, large units of DNA that encode instructions for that cell to grow, divide, and carry out its specialized functions. During mitosis, when a cell divides, each of these chromosomes must be accurately distributed to the two new daughter cells. If this process occurs incorrectly for even a single chromosome, the resulting daughter cells will lose or gain thousands of genes and the instructions that they contain. This type of error in chromosome segregation can result in the death of the cell and is thought to contribute to tumorigenesis. Indeed, more than 70% of tumors are observed to have abnormal numbers of chromosomes. In addition to errors that alter whole chromosome numbers, in cases where the cellular machinery makes inappropriate attachments to the chromosomes, this can result in chromosome fragmentation during cell division. These errors have been shown to cause chromosomal rearrangements, which also have the potential to result in cellular transformation and tumorigenesis. To facilitate the segregation of DNA during mitosis, chromosomes must generate physical attachments to rod-like polymers termed microtubules that provide the structure and forces to move the chromosomes. A key player in chromosome segregation is a large proteinaceous structure termed the kinetochore that forms the interface between chromosomes and microtubules. Inhibition of kinetochore activities is predicted to target cancer cells while avoiding the dose-limiting neuronal toxicity associated with microtubule-binding chemotherapeutics. Determining the molecular basis for kinetochore function is crucial to understand the defective processes that can give rise to tumor cells, and to evaluate the best targets for the diagnosis and treatment of disease. The proposed work will analyze the mechanisms by which kinetochores interact with spindle microtubule polymers in human cells. We will take parallel cellular and biochemical approaches to analyze the key proteins that bind to microtubules at kinetochores. A key focus of this work will be not only to analyze the functions and activities of the individual proteins, but also to test how the multiple different proteins that are present at kinetochores act together in a integrated manner to form robust interactions with microtubules.

Public Health Relevance

Defects in mitosis that result in errors in chromosome numbers can cause the death of a cell and are thought to contribute to tumor progression. Understanding the means by which these units of DNA, and the genetic information that they contain, are evenly distributed to new cells is critical for the diagnosis and treatment of cancer. This proposed work will determine the mechanisms that direct and control chromosome segregation in human cells by analyzing the connections between chromosomes and the rod-like microtubule polymers that provide the structure and force to segregate the DNA.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM088313-07
Application #
8918663
Study Section
Nuclear and Cytoplasmic Structure/Function and Dynamics Study Section (NCSD)
Program Officer
Deatherage, James F
Project Start
2009-08-01
Project End
2018-06-30
Budget Start
2015-07-01
Budget End
2016-06-30
Support Year
7
Fiscal Year
2015
Total Cost
Indirect Cost
Name
Whitehead Institute for Biomedical Research
Department
Type
DUNS #
120989983
City
Cambridge
State
MA
Country
United States
Zip Code
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Monda, Julie K; Cheeseman, Iain M (2018) Nde1 promotes diverse dynein functions through differential interactions and exhibits an isoform-specific proteasome association. Mol Biol Cell 29:2336-2345
Monda, Julie K; Cheeseman, Iain M (2018) Dynamic regulation of dynein localization revealed by small molecule inhibitors of ubiquitination enzymes. Open Biol 8:
Monda, Julie K; Cheeseman, Iain M (2018) The kinetochore-microtubule interface at a glance. J Cell Sci 131:
Su, Kuan-Chung; Tsang, Mary-Jane; Emans, Neil et al. (2018) CRISPR/Cas9-based gene targeting using synthetic guide RNAs enables robust cell biological analyses. Mol Biol Cell 29:2370-2377
McKinley, Kara L; Cheeseman, Iain M (2017) Large-Scale Analysis of CRISPR/Cas9 Cell-Cycle Knockouts Reveals the Diversity of p53-Dependent Responses to Cell-Cycle Defects. Dev Cell 40:405-420.e2
Kern, David M; Monda, Julie K; Su, Kuan-Chung et al. (2017) Astrin-SKAP complex reconstitution reveals its kinetochore interaction with microtubule-bound Ndc80. Elife 6:
Monda, Julie K; Whitney, Ian P; Tarasovetc, Ekaterina V et al. (2017) Microtubule Tip Tracking by the Spindle and Kinetochore Protein Ska1 Requires Diverse Tubulin-Interacting Surfaces. Curr Biol 27:3666-3675.e6
Kern, David M; Nicholls, Peter K; Page, David C et al. (2016) A mitotic SKAP isoform regulates spindle positioning at astral microtubule plus ends. J Cell Biol 213:315-28
McKinley, Kara L; Cheeseman, Iain M (2016) The molecular basis for centromere identity and function. Nat Rev Mol Cell Biol 17:16-29

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