Figure 6.
Three HP1 populations with different mobilities in mammalian cell nuclei. The diagram summarizes the kinetic data of HP1 obtained by FCS and FRAP. Euchromatin (EU) and heterochromatin (HC) contain two differently mobile HP1 populations, a highly mobile fraction with a FRAP recovery half-time (t1/2) of ∼1 s (D: diffusion coefficient), and a less mobile with a t1/2 of ∼10 s. In addition, there is a minor fraction of very slow HP1 molecules of 5–7% present in constitutive heterochromatin.