title: The R362A mutation at the C-terminus of CA inhibits packaging of human immunodeficiency virus type 1 RNA.
abstract: The capsid (CA) sequence of human immunodeficiency virus type 1 (HIV-1) Gag protein consists of two independently folded domains named the N-terminal domain (NTD) and C-terminal domain (CTD) that are connected by a flexible linker. Most of the CTD sequence adopts rigid structure except for the last 11 amino acids (positions 354 to 364) that are disordered even in the context of the downstream SP1 and nucleocapsid (NC) sequence. Although disordered, this short peptide region plays a crucial role in HIV-1 replication. In this study, we identified three second-site mutations within Gag named A238T, G358S, and N373K that rescued a deleterious mutation R362A located at the C-terminus of CA. A238T is located within the NTD of CA, G358S and N373K are positioned proximal to R362A. One of the mechanisms underlying this compensation event is correction of reduced packaging of viral RNA into the R362A mutated viruses, as shown by the results of RNase protection assays, native Northern blots experiments as well as filter-binding assays. These data suggest that one potential function for the C-terminal disordered sequence of CA in HIV-1 replication is to regulate HIV-1 RNA packaging.
authors.affiliation: McGill AIDS Centre, Lady Davis Institute-Jewish General Hospital, 3755 Cote Ste-Catherine Road, Montreal, Quebec, Canada H3T 1E2.
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Guo
authors.forename: Bibhuti Bhusan
authors.initials: BB
authors.lastname: Roy
authors.forename: Jing
authors.initials: J
authors.lastname: Hu
authors.forename: Ariel
authors.initials: A
authors.lastname: Roldan
authors.forename: Mark A
authors.initials: MA
authors.lastname: Wainberg
authors.forename: Chen
authors.initials: C
authors.lastname: Liang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D019556:COS Cells; D036022:Capsid Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D002522:Chlorocebus aethiops; D003198:Computer Simulation; D004279:DNA, Viral / Q000235:genetics; D015683:Gene Products, gag / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D015497:HIV-1 / Q000235:genetics* / Q000502:physiology / Q000648:ultrastructure; D006367:HeLa Cells; D006801:Humans; D008854:Microscopy, Electron; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017354:Point Mutation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012367:RNA, Viral / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D014162:Transfection; D019065:Virus Assembly
chemical_list: D036022:Capsid Proteins; D004279:DNA, Viral; D015683:Gene Products, gag; D012367:RNA, Viral; D011994:Recombinant Proteins