ASF1A
Description
The ASF1A (anti-silencing function 1A histone chaperone) is a protein-coding gene located on chromosome 6.
ASF1A is a human protein encoded by the ASF1A gene. It is a histone chaperone, similar to the anti-silencing function-1 gene in yeast, and is a key component of a histone donor complex involved in nucleosome assembly. ASF1A interacts with histones H3 and H4 and functions with a chromatin assembly factor during DNA replication and repair. It interacts with proteins like TLK1, TLK2, CHAF1B, and CHAF1A.
ASF1A is a histone chaperone that facilitates histone deposition, exchange, and removal during nucleosome assembly and disassembly. It works with CAF-1 to promote replication-dependent chromatin assembly and with HIRA to promote replication-independent chromatin assembly. ASF1A is essential for homologous recombination-mediated repair of double-strand breaks (DSBs) at stalled or collapsed replication forks. It facilitates histone replacement at DSBs, leading to recruitment of the MMS22L-TONSL complex and subsequent loading of RAD51. ASF1A is also involved in the nuclear import of the histone H3-H4 dimer together with importin-4 (IPO4). Specifically, it recognizes and binds newly synthesized histones with the monomethylation of H3 'Lys-9' and acetylation at 'Lys-14' (H3K9me1K14ac) marks, and diacetylation at 'Lys-5' and 'Lys-12' of H4 (H4K5K12ac) marks in the cytosol. ASF1A is required for the formation of senescence-associated heterochromatin foci (SAHF) and efficient senescence-associated cell cycle exit.
ASF1A is also known as CGI-98, CIA, HSPC146.
