Biological process

fHC assembly, facultative heterochromatin assembly

The compaction of chromatin into a conformation that is refactory to transcription but that be converted to euchromatin and allow transcription in specific contexts. These can be temporal (e.g., developmental states or specific cell-cycle stages), spatial (e.g., nuclear localization changes from the center to the periphery or vice versa due to exogenous factors/signals), or parental/heritable (e.g., monoallelic gene expression).

Note that facultative heterochromatin can be reprogrammed, as opposed to constitutive heterochromatin which usually cannot be reprogrammed to a transcriptionally-competent state.