For chromosomal locus imaging in Figure 1 , CRISPR imaging was used to visualize the location of the Chr3q29, Chr1p36, and Chr13q34 loci. Stable cell lines expressing CRISPR-EChO, dCas9-HaloTag, and sgRNA were seeded in 24-well μ-plate (Ibidi 82406) and treated with 100 μM abscisic acid (Sigma A1049) or DMSO (Sigma D2650) vehicle for 8 to 24 h. Cells were stained with JF549-HaloTag ligand (gift from Luke Lavis in Janelia Research Campus(Grimm et al., 2015 (link))) at 10 nM for 15 m at 37°C in culture media. Cells were then washed twice with culture media, incubating for 30 m at 37°C during the second wash, then replaced with culture media containing fresh inducer before imaging.
For mCherry-HP1α imaging, U2OS cells stably expressing CRISPR-EChO and sgRNA were seeded at 10% confluence in 24-well μ-plate (Ibidi 82406) and treated with 100 μM abscisic acid or DMSO vehicle for 2 days before imaging.
For mCherry-HP1α imaging, U2OS cells stably expressing CRISPR-EChO and sgRNA were seeded at 10% confluence in 24-well μ-plate (Ibidi 82406) and treated with 100 μM abscisic acid or DMSO vehicle for 2 days before imaging.