Histone chaperones regulate histone exchange during transcription.
Transcription by RNA polymerase II is accompanied by dynamic changes in chromatin, including the eviction/deposition of nucleosomes or the covalent modification of histone subunits. This study examined the role of the histone H3/H4 chaperones, Asf1 and HIR, in histone mobility during transcription, with particular focus on the histone exchange pathway, using a dual histone expression system. The results showed that the exchange of H3/H4 normally occurs during transcription by the histone chaperones. Both Asf1 and HIR are important for histone deposition but have a different effect on histone exchange. While Asf1 mediated incorporation of external H3/H4 and renewal of pre-existing histones, HIR opposed it. The balance of two opposing activities might be an important mechanism for determining current chromatin states.
Kim
Hye-Jin
HJ
College of Pharmacy, Sungkyunkwan University, Suwon, Gyeonggi-do, Republic of Korea.
Seol
Ja-Hwan
JH
Han
Jeung-Whan
JW
Youn
Hong-Duk
HD
Cho
Eun-Jung
EJ
D018797:Cell Cycle Proteins / Q000737:chemistry; D005656:Fungal Proteins / Q000378:metabolism; D017353:Gene Deletion; D020868:Gene Silencing; D006657:Histones / Q000737:chemistry / Q000378:metabolism*; D018832:Molecular Chaperones / Q000378:metabolism*; D009154:Mutation; D009687:Nuclear Proteins / Q000378:metabolism; D009707:Nucleosomes / Q000378:metabolism; D012319:RNA Polymerase II / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000378:metabolism; D014158:Transcription, Genetic
C109731:ASF1 protein, S cerevisiae; D018797:Cell Cycle Proteins; D005656:Fungal Proteins; C078808:HIR1 protein, S cerevisiae; D006657:Histones; D018832:Molecular Chaperones; D009687:Nuclear Proteins; D009707:Nucleosomes; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D012319:RNA Polymerase II