Barrier-to-autointegration factor (BAF) condenses DNA by looping.
Barrier-to-autointegration factor (BAF) is a protein that has been proposed to compact retroviral DNA, making it inaccessible as a target for self-destructive integration into itself (autointegration). BAF also plays an important role in nuclear organization. We studied the mechanism of DNA condensation by BAF using total internal reflection fluorescence microscopy. We found that BAF compacts DNA by a looping mechanism. Dissociation of BAF from DNA occurs with multiphasic kinetics; an initial fast phase is followed by a much slower dissociation phase. The mechanistic basis of the broad timescale of dissociation is discussed. This behavior mimics the dissociation of BAF from retroviral DNA within preintegration complexes as monitored by functional assays. Thus the DNA binding properties of BAF may alone be sufficient to account for its association with the preintegration complex.
Skoko
Dunja
D
Laboratory of Molecular Biology, Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
Li
Min
M
Huang
Ying
Y
Mizuuchi
Michiyo
M
Cai
Mengli
M
Bradley
Christina M
CM
Pease
Paul J
PJ
Xiao
Botao
B
Marko
John F
JF
Craigie
Robert
R
Mizuuchi
Kiyoshi
K
D001665:Binding Sites; D002352:Carrier Proteins; D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D019281:Dimerization; D006801:Humans; D008856:Microscopy, Fluorescence; D011487:Protein Conformation; D017510:Protein Folding
D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D004247:DNA