title: Targeting and tracing of specific DNA sequences with dTALEs in living cells.
abstract: Epigenetic regulation of gene expression involves, besides DNA and histone modifications, the relative positioning of DNA sequences within the nucleus. To trace specific DNA sequences in living cells, we used programmable sequence-specific DNA binding of designer transcription activator-like effectors (dTALEs). We designed a recombinant dTALE (msTALE) with variable repeat domains to specifically bind a 19-bp target sequence of major satellite DNA. The msTALE was fused with green fluorescent protein (GFP) and stably expressed in mouse embryonic stem cells. Hybridization with a major satellite probe (3D-fluorescent in situ hybridization) and co-staining for known cellular structures confirmed in vivo binding of the GFP-msTALE to major satellite DNA present at nuclear chromocenters. Dual tracing of major satellite DNA and the replication machinery throughout S-phase showed co-localization during mid to late S-phase, directly demonstrating the late replication timing of major satellite DNA. Fluorescence bleaching experiments indicated a relatively stable but still dynamic binding, with mean residence times in the range of minutes. Fluorescently labeled dTALEs open new perspectives to target and trace DNA sequences and to monitor dynamic changes in subnuclear positioning as well as interactions with functional nuclear structures during cell cycle progression and cellular differentiation.
authors.affiliation: Department of Biology II, Humanbiology and Bioimaging, Center for Integrated Protein Science Munich (CIPSM), Ludwig Maximilians University Munich, 82152 Planegg-Martinsried, Germany and Department of Biology I, Genetics, Ludwig Maximilians University Munich, 82152 Planegg-Martinsried, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Thanisch
authors.forename: Katrin
authors.initials: K
authors.lastname: Schneider
authors.forename: Robert
authors.initials: R
authors.lastname: Morbitzer
authors.forename: Irina
authors.initials: I
authors.lastname: Solovei
authors.forename: Thomas
authors.initials: T
authors.lastname: Lahaye
authors.forename: Sebastian
authors.initials: S
authors.lastname: Bultmann
authors.forename: Heinrich
authors.initials: H
authors.lastname: Leonhardt
mesh_terms: D000818:Animals; D002453:Cell Cycle / Q000235:genetics; D002460:Cell Line; D004276:DNA, Satellite / Q000032:analysis*; D004268:DNA-Binding Proteins / Q000032:analysis / Q000235:genetics; D053595:Embryonic Stem Cells / Q000737:chemistry; D005456:Fluorescent Dyes; D049452:Green Fluorescent Proteins / Q000032:analysis / Q000235:genetics; D057809:HEK293 Cells; D006801:Humans; D051379:Mice; D011993:Recombinant Fusion Proteins / Q000032:analysis
chemical_list: D004276:DNA, Satellite; D004268:DNA-Binding Proteins; D005456:Fluorescent Dyes; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins