Development of a heterochromatin targeting
peptide probe. (A–H)
Confocal microscopy images of 3T3 fibroblasts treated with the indicated
peptides. SiR fluorescence emission of the indicated peptide probes
(magenta) is overlaid with HP1α-mEOs3.2 fluorescence (cyan).
2D intensity profiles corresponding to the dotted lines displayed
on the images (line scans) are depicted to the right of the micrographs.
(I) Confocal microscopy images and line scans of 3T3 fibroblasts treated
with CP-SiR probe (i.e., T23-SN3-SiR, top) or the K9A variant CP′-SiR. J) Correlation between HP1α-mEOs3.2 and CP-SiR or CP′-SiR staining, demonstrating
good colocalization for CP-SiR, and the dependence on
the presence of the H3K9me3 modification in CP-SiR for
heterochromatin staining (see Supporting Information for details on the calculation). N = 21 cells (CP-SiR), N = 10 cells (CP′-SiR). PCC: Pearson
correlation coefficient.Two-sample t test: *p < 4 × 10–7, scale bars: 10 μm.