title: Spectral imaging to visualize higher-order genomic organization.
abstract: A concern in the field of genomics is the proper interpretation of large, high-throughput sequencing datasets. The use of DNA FISH followed by high-content microscopy is a valuable tool for validation and contextualization of frequently occurring gene pairing events at the single-cell level identified by deep sequencing. However, these techniques possess certain limitations. Firstly, they do not permit the study of colocalization of many gene loci simultaneously. Secondly, the direct assessment of the relative position of many clustered gene loci within their respective chromosome territories is impossible. Thus, methods are required to advance the study of higher-order nuclear and cellular organization. Here, we describe a multiplexed DNA FISH technique combined with indirect immunofluorescence to study the relative position of 6 distinct genomic or cellular structures. This can be achieved in a single hybridization step using spectral imaging during image acquisition and linear unmixing. Here, we detail the use of this method to quantify gene pairing between highly expressed spliceosomal genes and compare these data to randomly positioned in silico simulated gene clusters. This is a potentially universally applicable approach for the validation of 3C-based technologies, deep imaging of spatial organization within the nucleus and global cellular organization.
authors.affiliation: a Department of Cell Biology , Rosalind Franklin University of Medicine & Science, Chicago Medical School , North Chicago , IL , USA.|b Laboratory of Receptor Biology and Gene Expression , National Cancer Institute, National Institutes of Health , Bethesda , MD , USA.
authors.forename: Iain A
authors.initials: IA
authors.lastname: Sawyer
authors.affiliation: a Department of Cell Biology , Rosalind Franklin University of Medicine & Science, Chicago Medical School , North Chicago , IL , USA.
authors.forename: Sergei P
authors.initials: SP
authors.lastname: Shevtsov
authors.affiliation: a Department of Cell Biology , Rosalind Franklin University of Medicine & Science, Chicago Medical School , North Chicago , IL , USA.
authors.forename: Miroslav
authors.initials: M
authors.lastname: Dundr
mesh_terms: D004247:DNA / Q000235:genetics; D005455:Fluorescent Antibody Technique; D023281:Genomics / Q000379:methods*; D006367:HeLa Cells; D006801:Humans; D017404:In Situ Hybridization, Fluorescence / Q000379:methods*; D008853:Microscopy
chemical_list: D004247:DNA
keywords: Cajal bodies; DNA FISH; chromosome territories; gene positioning; genome organization; nuclear bodies; spectral imaging; spliceosomal U snRNA genes