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#histone chaperone

2 public questions tagged with this topic.

Which histone chaperone mainly handles H2A-H2B dimers?

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 remodel

Ref: Mosammaparast et al., PNAS, NAP1 Histone Chaperone Handles H2A-H2B Dimers, Assembly Mechanism

Which histone chaperone deposits H3-H4 during DNA replication?

During S phase newly synthesized histones deposited behind replication fork by dedicated chaperone complexes ensuring rapid nucleosome reassembly and genome stability. CAF-1 complex comprising three subunits p150, p60, p48 specifically binds proliferating cell nuclear antigen PCNA at replication fork and hands H3-H4 dimers to assembling DNA, coupling nucleosome formation to synthesis. NAP1 chaperones H2A-H2B dimers, ASF1 transfers H3-H4 dimers to CAF-1 and HIRA variant pathway, FACT facilitates transcription elongation through nucleosomes allowing polymerase passage. CAF-1 depletion causes S p

Ref: Smith and Stillman 1989 CAF-1 Discovery; Alberts et al., Chapter 5: CAF-1 Deposits H3-H4 During Replication