The histone H1 C-terminal domain binds to the apoptotic nuclease, DNA fragmentation factor (DFF40/CAD) and stimulates DNA cleavage.
The apoptotic nuclease, DNA fragmentation factor (DFF40/CAD), is primarily responsible for internucleosomal DNA cleavage during the terminal stages of programmed cell death. Previously, we demonstrated that histone H1 greatly stimulates naked DNA cleavage by this nuclease. Here, we investigate the mechanism of this stimulation with native and recombinant mouse and human histone H1 species. Using a series of truncation mutants of recombinant histone H1-0, we demonstrate that the H1 C-terminal domain (CTD) is responsible for activation of DFF40/CAD. We show further that the intact histone H1-0 CTD and certain synthetic CTD fragments bind to DFF40/CAD and confer upon it an increased ability to bind to DNA. Interestingly, we find that each of the six somatic cell histone H1 isoforms, whose CTDs differ significantly in primary sequence but not amino acid composition, equally activate DFF40/CAD. We conclude that the interactions identified here between the histone H1 CTD and DFF40/CAD target and activate linker DNA cleavage during the terminal stages of apoptosis.
Widlak
Piotr
P
Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75235, USA.
Kalinowska
Magdalena
M
Parseghian
Missag H
MH
Lu
Xu
X
Hansen
Jeffrey C
JC
Garrard
William T
WT
D000818:Animals; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins; D001665:Binding Sites; D004247:DNA / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism; D003851:Deoxyribonucleases / Q000378:metabolism*; D004789:Enzyme Activation; D006657:Histones / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D006868:Hydrolysis; D051379:Mice; D010446:Peptide Fragments / Q000737:chemistry* / Q000378:metabolism; D000075223:Poly-ADP-Ribose Binding Proteins; D011485:Protein Binding; D020033:Protein Isoforms / Q000737:chemistry / Q000378:metabolism; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism; D013379:Substrate Specificity
D051017:Apoptosis Regulatory Proteins; D004268:DNA-Binding Proteins; D006657:Histones; D010446:Peptide Fragments; D000075223:Poly-ADP-Ribose Binding Proteins; D020033:Protein Isoforms; D011506:Proteins; C109664:caspase-activated DNase inhibitor; D004247:DNA; C113696:DFFB protein, human; D003851:Deoxyribonucleases