Figure 2
Pair correlation analysis of HP1 alpha molecular flow with respect to heterochromatin foci.
N&B analysis of HP1-α oligomerization. (A) Region of interest selected for pair correlation analysis in a NIH3T3 nucleus expressing free EGFP with the DNA stained by Hoechst 33342. (B) Intensity profile of free EGFP overlaid with the intensity profile of Hoechst 33342 along the selected region of interest reveals a heterochromatin region between pixels 8–16. (C) Region of interest in (A) pseudo-colored according to the brightness distribution of free EGFP (green = monomer, yellow = dimer, red = higher order oligomer). (D) Line scan acquired along the region of interest in the EGFP channel reveals an exclusion from the heterochromatin region. (E) Pair correlation analysis of free EGFP molecular flow with respect to a compact chromatin density region. (F) Average pair correlation profile for EGFP molecular flow in regions of heterochromatin foci (N = 10 cells) reveals molecular mobility on a time scale of 1–5 ms. (G) Region of interest selected for pair correlation analysis in a NIH3T3 nucleus expressing HP1-α-EGFP. (H) Intensity profile of HP1-α-EGFP overlaid with the intensity profile of Hoechst 33342 along the selected region of interest reveals a heterochromatin region between pixels 4–12 and 20–28. (I) Region of interest in (G) pseudo-colored according to the brightness distribution of HP1-α-EGFP (green = monomer, yellow = dimer, red = higher order oligomer). (J) Line scan acquired along the region of interest in the HP1-α-EGFP channel reveals a co-localisation with the heterochromatin regions. (K) Pair correlation analysis of HP1-α-EGFP molecular flow with respect to heterochromatin foci reveals multiple bands of correlation at the edges of the foci. pCF(6) in (E) and (G) indicates that pair correlation function is calculated at the distance of 6 pixels along the scanned line (see also Methods for further details). (L) Average pair correlation profile for HP1-α-EGFP molecular flow in regions of heterochromatin foci (N = 10 cells) molecular mobility on a timescale of 1–5 ms and then re-appearance due to a potential rotation from 5–10 ms and 20–100 ms.
