@inbook{007f273b36fc415cb18f8fc408e341ad,
title = "Measuring Cytological Proximity of Chromosomal Loci to Defined Nuclear Compartments with TSA-seq",
abstract = "Distinct nuclear structures and bodies are involved in genome intranuclear positioning. Measuring proximity and relative distances of genomic loci to these nuclear compartments, and correlating this chromosome intranuclear positioning with epigenetic marks and functional readouts genome-wide, will be required to appreciate the true extent to which this nuclear compartmentalization contributes to regulation of genome functions. Here we present detailed protocols for TSA-seq, the first sequencing-based method for estimation of cytological proximity of chromosomal loci to spatially discrete nuclear structures, such as nuclear bodies or the nuclear lamina. TSA-seq uses Tyramide Signal Amplification (TSA) of immunostained cells to create a concentration gradient of tyramide–biotin free radicals which decays exponentially as a function of distance from a point-source target. Reaction of these free radicals with DNA deposits tyramide–biotin onto DNA as a function of distance from the point source. The relative enrichment of this tyramide-labeled DNA versus input DNA, revealed by DNA sequencing, can then be used as a “cytological ruler” to infer relative, or even absolute, mean chromosomal distances from immunostained nuclear compartments. TSA-seq mapping is highly reproducible and largely independent of the target protein or antibody choice for labeling a particular nuclear compartment. Our protocols include variations in TSA labeling conditions to provide varying spatial resolution as well as enhanced sensitivity. Our most streamlined protocol produces TSA-seq spatial mapping over a distance range of ~1 micron from major nuclear compartments using ~10–20 million cells.",
keywords = "Gene position, Genome organization, Nuclear bodies, Nuclear compartments, Proximity labeling, TSA-seq",
author = "Liguo Zhang and Yu Chen and Belmont, {Andrew S.}",
note = "We thank Drs. William Brieher, Brian Freeman, K.V. Prasanth, and Lisa Stubbs (UIUC, Urbana, IL) for helpful suggestions in developing these protocols. We also thank Belmont laboratory members for reagents and suggestions. We thank the UIUC Biotechnology center for guidance with DNA sonication and sequencing library preparation. We thank Drs. Jian Ma, Bas van Steensel, David Gilbert, and Huimin Zhao from the Belmont 4DN NOFIC U54 Center and other members of the 4D-Nucleome Consortium for helpful suggestions and feedback. This work was supported by National Institutes of Health grants R01GM58460 (ASB) and U54 DK107965 (ASB). Author contributions: ASB conceptualized the TSA-seq idea and supervised the development of TSA-seq 1.0 and 2.0. YC developed TSA-seq 1.0 with protocols for tyramide–biotin labeling, TSA cell labeling, genomic DNA purification and fragmentation, dot blot and biotinylated DNA bead pulldown, contributed by LZ for Condition 3 (DTT). LZ developed TSA-seq 2.0, added protocols for TSA adherent cell labeling and Drosophila DNA spike in controls, and optimized protocols/methods for TSA labeling, genomic DNA purification and fragmentation, dot blot, and sequencing library construction. LZ, ASB, and YC prepared the manuscript. We thank Drs. William Brieher, Brian Freeman, K.V. Prasanth, and Lisa Stubbs (UIUC, Urbana, IL) for helpful suggestions in developing these protocols. We also thank Belmont laboratory members for reagents and suggestions. We thank the UIUC Biotechnology center for guidance with DNA sonication and sequencing library preparation. We thank Drs. Jian Ma, Bas van Steensel, David Gilbert, and Huimin Zhao from the Belmont 4DN NOFIC U54 Center and other members of the 4D-Nucleome Consortium for helpful suggestions and feedback. This work was supported by National Institutes of Health grants R01GM58460 (ASB) and U54 DK107965 (ASB).",
year = "2022",
doi = "10.1007/978-1-0716-2497-5_8",
language = "English (US)",
series = "Methods in Molecular Biology",
publisher = "Humana Press Inc.",
pages = "145--186",
booktitle = "Methods in Molecular Biology",
}