Author:

Keywords:

Science & Technology, Life Sciences & Biomedicine, Biochemistry & Molecular Biology, LEUKEMIA-VIRUS INTEGRASE, RETROVIRAL DNA INTEGRATION, HIV-1 INTEGRASE, FUNCTIONAL DOMAINS, CRYSTAL-STRUCTURE, BINDING DOMAIN, PROTEIN, ORGANIZATION, TARGET, COMPLEMENTATION, Cell Cycle, Cell Nucleus, Cytoplasm, Genetic Vectors, HEK293 Cells, HeLa Cells, Humans, Integrases, Mitosis, Moloney murine leukemia virus, Protein Structure, Quaternary, Proteins, Virus Integration, Hela Cells, C14/16/053#53765158, 05 Environmental Sciences, 06 Biological Sciences, 08 Information and Computing Sciences, Developmental Biology, 31 Biological sciences, 34 Chemical sciences, 41 Environmental sciences

Abstract:

The Moloney murine leukemia virus (MLV) is a prototype gammaretrovirus requiring nuclear disassembly before DNA integration. In the nucleus, integration site selection towards promoter/enhancer elements is mediated by the host factor bromo- and extraterminal domain (BET) proteins (bromodomain (Brd) proteins 2, 3 and 4). MLV-based retroviral vectors are used in gene therapy trials. In some trials leukemia occurred through integration of the MLV vector in close proximity to cellular oncogenes. BET-mediated integration is poorly understood and the nature of integrase oligomers heavily debated. Here, we created wild-type infectious MLV vectors natively incorporating fluorescent labeled IN and performed single-molecule intensity and Förster resonance energy transfer experiments. The nuclear localization of the MLV pre-integration complex neither altered the IN content, nor its quaternary structure. Instead, BET-mediated interaction of the MLV intasome with chromatin in the post-mitotic nucleus reshaped its quaternary structure.