A Stable Complex Between Integrase and Viral DNA Ends Mediates Human Immunodeficiency Virus Integration In vitro

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 91; no. 15; pp. 7316 - 7320
• Main Authors: Ellison, Viola, Brown, Patrick O.
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences of the United States of America 19.07.1994; National Acad Sciences
• Subjects: AIDS/HIV; Base Sequence; Binding sites; Biochemistry; Cations, Divalent; Divalent cations; DNA; DNA Nucleotidyltransferases - metabolism; DNA, Viral - metabolism; HIV; HIV 1; HIV-1 - genetics; HIV-1 - physiology; human immunodeficiency virus; Integrases; Molecular Sequence Data; Molecules; Nucleoproteins; Oligonucleotides; Sequence Deletion; Viral DNA; Virus Integration
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.91.15.7316

Retroviral replication depends on integration of the viral genome into a chromosome of the host cell. The steps in this process are orchestrated in vivo by a large nucleoprotein complex and are catalyzed by the retroviral enzyme integrase. Several biochemical properties of the in vivo nucleoprotein complex were reproduced in vitro with purified integrase of human immunodeficiency virus type 1 and model viral DNA substrates. A stable complex between integrase and viral DNA was detected as an early intermediate in the integration reaction. After formation of this initial complex, the enzyme processively catalyzed the 3' end processing and strand transfer steps in the reaction. Complexes containing only purified integrase and the model viral DNA end were stable under a variety of conditions and efficiently used nonviral DNA molecules as integration targets. These complexes required a divalent cation for their formation, and their stability was highly dependent on the 5'-terminal dinucleotide of the viral DNA, for which no functional role has previously been defined. Thus, interactions between integrase and the extreme ends of the viral DNA molecule may be sufficient to account for the stability of the in vivo integration complex.