Publications (3)7.96 Total impact
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Article: Histone H3 lysine 56 acetylation and the response to DNA replication fork damage.
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ABSTRACT: In Saccharomyces cerevisiae, histone H3 lysine 56 acetylation (H3K56ac) occurs in newly synthesized histones that are deposited throughout the genome during DNA replication. Defects in H3K56ac sensitize cells to genotoxic agents, suggesting that this modification plays an important role in the DNA damage response. However, the links between histone acetylation, the nascent chromatin structure, and the DNA damage response are poorly understood. Here we report that cells devoid of H3K56ac are sensitive to DNA damage sustained during transient exposure to methyl methanesulfonate (MMS) or camptothecin but are only mildly affected by hydroxyurea. We demonstrate that, after exposure to MMS, H3K56ac-deficient cells cannot complete DNA replication and eventually segregate chromosomes with intranuclear foci containing the recombination protein Rad52. In addition, we provide evidence that these phenotypes are not due to defects in base excision repair, defects in DNA damage tolerance, or a lack of Rad51 loading at sites of DNA damage. Our results argue that the acute sensitivity of H3K56ac-deficient cells to MMS and camptothecin stems from a failure to complete the repair of specific types of DNA lesions by recombination and/or from defects in the completion of DNA replication.Molecular and cellular biology 01/2012; 32(1):154-72. · 6.06 Impact Factor -
Article: Imaging the mitotic spindle.
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ABSTRACT: The mitotic spindle, due to its striking form, has been imaged for well over 100 years. Composed largely of microtubules and chromosomes, the spindle also contains numerous proteins whose roles include biochemical and biophysical regulation of mitosis. Given the transient, dynamic nature of the spindle, the light microscope continues to be the main tool employed to unlock its mysteries. In this chapter, we will discuss modern light microscopy techniques commonly used for imaging this intricate cellular machine as well as provide examples and protocols. We will also describe some biological preparations and experimental regimes for investigation of the mitotic spindle.Methods in enzymology 01/2012; 505:81-103. · 1.90 Impact Factor -
Chapter: From Live-Cell Microscopy to Molecular Mechanisms: Deciphering the Functions of Kinetochore Proteins
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ABSTRACT: The goal of cell biology research is to explain cell behavior as a function of the dynamics of subcellular molecular assemblies. Live-cell light microscopy has emerged as the method of choice for probing molecular function in a nearphysiological environment. However, light-microscopy data are on the cellular scale, while data interpretation occurs on the molecular scale. To bridge the gap between these two scales, empirical mathematical models of the relationship between molecular action and cellular behavior must be devised and calibrated using the experimental data. In this chapter we discuss several necessary steps to achieve this task. First, experiments should be designed such that the molecular action of interest is probed with sufficient spatial and temporal resolution and such that the resulting imagery is amenable to computational analysis. Second, automated image analysis tools must be developed to extract from the experiments reliable and reproducible quantitative data necessary for model calibration. Third, since molecular action is generally stochastic, experimental data and model simulation results cannot be compared directly. Rather, they have to be analyzed to obtain a set of descriptors that allows their indirect comparison for the purpose of model calibration. These descriptors should be complete, unique and sensitive. Throughout the chapter, we illustrate these steps using the regulation of microtubule dynamics by kinetochore proteins during chromosome segregation as an illustrative example.12/2006: pages 265-285;
