title: Following DNA Compaction During the Cell Cycle by X-ray Nanodiffraction.
abstract: X-ray imaging of intact biological cells is emerging as a complementary method to visible light or electron microscopy. Owing to the high penetration depth and small wavelength of X-rays, it is possible to resolve subcellular structures at a resolution of a few nanometers. Here, we apply scanning X-ray nanodiffraction in combination with time-lapse bright-field microscopy to nuclei of 3T3 fibroblasts and thus relate the observed structures to specific phases in the cell division cycle. We scan the sample at a step size of 250 nm and analyze the individual diffraction patterns according to a generalized Porod's law. Thus, we obtain information on the aggregation state of the nuclear DNA at a real space resolution on the order of the step size and in parallel structural information on the order of few nanometers. We are able to distinguish nucleoli, heterochromatin, and euchromatin in the nuclei and follow the compaction and decompaction during the cell division cycle.
authors.affiliation: Institute for X-ray Physics, University of Göttingen , Friedrich-Hund-Platz 1, Göttingen 37077, Germany.
authors.forename: Clément Y J
authors.initials: CY
authors.lastname: Hémonnot
authors.affiliation: Institute for X-ray Physics, University of Göttingen , Friedrich-Hund-Platz 1, Göttingen 37077, Germany.
authors.forename: Christiane
authors.initials: C
authors.lastname: Ranke
authors.affiliation: Institute for X-ray Physics, University of Göttingen , Friedrich-Hund-Platz 1, Göttingen 37077, Germany.
authors.forename: Oliva
authors.initials: O
authors.lastname: Saldanha
authors.affiliation: Institute for X-ray Physics, University of Göttingen , Friedrich-Hund-Platz 1, Göttingen 37077, Germany.
authors.forename: Rita
authors.initials: R
authors.lastname: Graceffa
authors.affiliation: Institute for X-ray Physics, University of Göttingen , Friedrich-Hund-Platz 1, Göttingen 37077, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Hagemann
authors.affiliation: Institute for X-ray Physics, University of Göttingen , Friedrich-Hund-Platz 1, Göttingen 37077, Germany.
authors.forename: Sarah
authors.identifier: 0000-0002-0009-1024
authors.initials: S
authors.lastname: Köster
mesh_terms: D002453:Cell Cycle; D002466:Cell Nucleolus; D004247:DNA / Q000737:chemistry*; D008854:Microscopy, Electron; D036103:Nanotechnology; D011859:Radiography; D014965:X-Rays
chemical_list: D004247:DNA
keywords: DNA compaction; X-ray nanodiffraction; biological cells; cell division cycle; nanostructure