All cells must appropriately package and organize their DNA to survive. While some degree of DNA superstructure is generated by supercoiling and the binding of small architectural proteins, multiprotein assemblies known as condensins are responsible for compacting DNA on a more global level. Condensin complexes are composed of ATPase subunits of the Structural Maintenance of Chromosomes (SMC) protein family as well as several accessory factors. The SMC components are flexible, extended coiled-coil proteins that couple ATP turnover to DNA compaction. The precise function of the accessory subunits and their organization with respect to the SMC subunits are unknown. Multiple mechanisms have been proposed to explain how condensins physically condense DNA, although certain salient features of these models are mutually exclusive and have not been experimentally validated. This proposal aims to employ a combination of biochemistry and electron microscopy to: 1) determine the global architecture of condensin particles, 2) elucidate the role of the accessory subunits in the condensin particle, and 3) apply data from these efforts toward testing specific models of condensin function. In order to compare and contrast the function of these assemblies across different cellular kingdoms, we will study two distinct condensin systems of different subunit composition and biochemical properties from yeast and bacteria. To enable these studies, we have: 1) expressed and purified all pertinent condensin assemblies and subassemblies, 2) begun to define the interaction of these complexes with DNA, and 3) have obtained initial reconstructions of condensin complexes from single particle images. Data obtained to date indicate the feasibility of our specific aims.
| Kellogg, Elizabeth H; Hejab, Nisreen M A; Poepsel, Simon et al. (2018) Near-atomic model of microtubule-tau interactions. Science 360:1242-1246 |
| Zhang, Rui; LaFrance, Benjamin; Nogales, Eva (2018) Separating the effects of nucleotide and EB binding on microtubule structure. Proc Natl Acad Sci U S A 115:E6191-E6200 |
| Nogales, Eva (2018) Cytoskeleton in high resolution. Nat Rev Mol Cell Biol 19:142 |
| Downing, Kenneth H; Glaeser, Robert M (2018) Estimating the effect of finite depth of field in single-particle cryo-EM. Ultramicroscopy 184:94-99 |
| Nogales, Eva (2018) Cryo-EM. Curr Biol 28:R1127-R1128 |
| Sazzed, Salim; Song, Junha; Kovacs, Julio A et al. (2018) Tracing Actin Filament Bundles in Three-Dimensional Electron Tomography Density Maps of Hair Cell Stereocilia. Molecules 23: |
| Kamennaya, Nina A; Zemla, Marcin; Mahoney, Laura et al. (2018) High pCO2-induced exopolysaccharide-rich ballasted aggregates of planktonic cyanobacteria could explain Paleoproterozoic carbon burial. Nat Commun 9:2116 |
| Howes, Stuart C; Geyer, Elisabeth A; LaFrance, Benjamin et al. (2018) Structural and functional differences between porcine brain and budding yeast microtubules. Cell Cycle 17:278-287 |
| Glaeser, Robert M (2018) PROTEINS, INTERFACES, AND CRYO-EM GRIDS. Curr Opin Colloid Interface Sci 34:1-8 |
| Han, Bong-Gyoon; Watson, Zoe; Cate, Jamie H D et al. (2017) Monolayer-crystal streptavidin support films provide an internal standard of cryo-EM image quality. J Struct Biol 200:307-313 |
Showing the most recent 10 out of 136 publications
