title: Super-resolution microscopy reveals decondensed chromatin structure at transcription sites.
abstract: Remodeling of the local chromatin structure is essential for the regulation of gene expression. While a number of biochemical and bioimaging experiments suggest decondensed chromatin structures are associated with transcription, a direct visualization of DNA and transcriptionally active RNA polymerase II (RNA pol II) at super-resolution is still lacking. Here we investigate the structure of chromatin isolated from HeLa cells using binding activatable localization microscopy (BALM). The sample preparation method preserved the structural integrity of chromatin. Interestingly, BALM imaging of the chromatin spreads revealed the presence of decondensed chromatin as gap structures along the spreads. These gaps were enriched with phosphorylated S5 RNA pol II, and were sensitive to the cellular transcriptional state. Taken together, we could visualize the decondensed chromatin regions together with active RNA pol II for the first time using super-resolution microscopy.
authors.affiliation: Mechanobiology Institute, Singapore.
authors.forename: Yejun
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Mechanobiology Institute, Singapore.
authors.forename: Shovamayee
authors.initials: S
authors.lastname: Maharana
authors.affiliation: 1] Laboratory of Atomic and Solid State Physics, Department of Physics [2] Howard Hughes Medical Institute Cornell University, Ithaca, New York 14853, USA.
authors.forename: Michelle D
authors.initials: MD
authors.lastname: Wang
authors.affiliation: 1] Mechanobiology Institute, Singapore [2] Department of Biological Sciences, National University of Singapore, Singapore.
authors.forename: G V
authors.initials: GV
authors.lastname: Shivashankar
mesh_terms: D002843:Chromatin / Q000648:ultrastructure*; D042002:Chromatin Assembly and Disassembly / Q000235:genetics; D004247:DNA / Q000648:ultrastructure*; D006367:HeLa Cells; D006657:Histones / Q000737:chemistry; D006801:Humans; D008853:Microscopy; D012319:RNA Polymerase II / Q000648:ultrastructure*; D014158:Transcription, Genetic; D015533:Transcriptional Activation / Q000235:genetics
chemical_list: D002843:Chromatin; D006657:Histones; D004247:DNA; D012319:RNA Polymerase II