DNA condensation by the nucleocapsid protein of HIV-1: a mechanism ensuring DNA protection.
The nucleocapsid (NC) protein NCp7 of the immunodeficiency virus type 1 is a small basic protein with two zinc finger motifs. NCp7 has key roles in virus replication and structure, which rely on its interactions with nucleic acids. Although most interactions involve RNAs, binding to the viral DNA is thought to be of importance to achieve protection of the DNA against cellular nucleases and its integration into the host genome. We investigated the interaction of NCp7 with plasmid DNA as a model system. The fluorescence probe YOYO-1 was used as the reporter. Binding of NCp7 to DNA caused DNA condensation, as inferred from the dramatic decrease in YOYO-1 fluorescence. Efficient condensation of DNA required the full length NCp7 with the zinc fingers. The fingerless peptide was less efficient in condensing DNA. Binding of both these NC peptides led to freezing of the segmental dynamics of DNA as revealed by anisotropy decay kinetics of YOYO-1. The truncated peptide NC(12-55) which retains the zinc fingers did not lead to DNA condensation despite its ability to bind and partially freeze the segmental motion of DNA. We propose that the histone-like property of NCp7 leading to DNA condensation contributes to viral DNA stability, in vivo.
Krishnamoorthy
G
G
Laboratoire de Pharmacologie et Physicochimie des interactions cellulaires et moléculaires, UMR 7034 du CNRS, Faculté de Pharmacie, Université Louis Pasteur de Strasbourg, 74 Route du Rhin, 67401 Illkirch, France. gk@tifr.res.in
Roques
Bernard
B
Darlix
Jean-Luc
JL
Mély
Yves
Y
D016880:Anisotropy; D001583:Benzoxazoles / Q000737:chemistry; D036022:Capsid Proteins / Q000737:chemistry / Q000378:metabolism*; D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D015683:Gene Products, gag / Q000737:chemistry / Q000378:metabolism*; D016679:Genome, Viral; D011485:Protein Binding; D011806:Quinolinium Compounds / Q000737:chemistry; D012367:RNA, Viral / Q000235:genetics / Q000378:metabolism; D013050:Spectrometry, Fluorescence; D013997:Time Factors; D014764:Viral Proteins; D054301:gag Gene Products, Human Immunodeficiency Virus
D001583:Benzoxazoles; D036022:Capsid Proteins; D015683:Gene Products, gag; C071884:NCP7 protein, Human immunodeficiency virus 1; D011806:Quinolinium Compounds; D012367:RNA, Viral; D014764:Viral Proteins; D054301:gag Gene Products, Human Immunodeficiency Virus; C075296:1,1'-((4,4,7,7-tetramethyl)-4,7-diazaundecamethylene)bis-4-(3-methyl-2,3-dihydro(benzo-1,3-oxazole)-2-methylidene)quinolinium; D004247:DNA