Practice question

Histone chaperones coordinate stepwise deposition of octamer components behind replication fork and at repair sites. NAP1 family members preferentially bind H2A-H2B dimers through acidic C-terminal domain, shielding positively charged surfaces and preventing non-specific DNA interactions. Structural data show NAP1 dimer holds one H2A-H2B dimer, delivering it to tetrasome to complete nucleosome assembly, and also extracts dimers during disassembly. In contrast, CAF-1 and ASF1 handle H3-H4. NAP1 also participates in H2A variant exchange, importin-mediated nuclear import and modulation of remodeler activity for transcriptional regulation.