title: Inositol phosphates compete with nucleic acids for binding to bovine leukemia virus matrix protein: implications for deltaretroviral assembly.
abstract: The matrix (MA) domain of retroviral Gag proteins plays a crucial role in virion assembly. In human immunodeficiency virus type 1 (HIV-1), a lentivirus, the presence of phosphatidylinositol-(4,5)-bisphosphate triggers a conformational change allowing the MA domain to bind the plasma membrane (PM). In this study, the MA protein from bovine leukemia virus (BLV) was used to investigate the mechanism of viral Gag binding to the membrane during replication of a deltaretrovirus. Fluorescence spectroscopy was used to measure the binding affinity of MA for two RNA constructs derived from the BLV genome as well as for single-stranded DNA (ssDNA). The importance of electrostatic interactions and the ability of inositol hexakisphosphate (IP6) to compete with nucleic acids for binding to MA were also investigated. Our data show that IP6 effectively competes with RNA and DNA for BLV MA binding, while [NaCl] of greater than 100 mM is required to produce any observable effect on DNA-MA binding. These results suggest that BLV assembly may be highly dependent on the specific interaction of the MA domain with components of the PM, as observed previously with HIV-1. The mode of MA binding to nucleic acids and the implications for BLV assembly are discussed.
authors.affiliation: Department of Chemistry, Berry College, Mt. Berry, Georgia 30149-5016, USA. dqualley@berry.edu
authors.forename: Dominic F
authors.initials: DF
authors.lastname: Qualley
authors.forename: Crystal M
authors.initials: CM
authors.lastname: Lackey
authors.forename: Justin P
authors.initials: JP
authors.lastname: Paterson
mesh_terms: D000818:Animals; D002417:Cattle; D016583:Enzootic Bovine Leukosis / Q000382:microbiology; D015683:Gene Products, gag / Q000378:metabolism*; D007295:Inositol Phosphates / Q000378:metabolism*; D001909:Leukemia Virus, Bovine / Q000502:physiology*; D009696:Nucleic Acids / Q000378:metabolism*; D013050:Spectrometry, Fluorescence; D014779:Virus Replication
chemical_list: D015683:Gene Products, gag; D007295:Inositol Phosphates; D009696:Nucleic Acids
keywords: RNA packaging; fluorescence spectroscopy; inositol phosphates; nucleic acid-binding proteins; retroviral Gag; retrovirus assembly