Open AccessSimian Immunodeficiency Virus Containing Mutations in N-Terminal Tyrosine Residues and in the PxxP Motif in Nef Replicates Efficiently in Rhesus Macaques
Author(s) -
Silke Carl,
A. John Iafrate,
Sabine M. Lang,
Nicole Stolte,
Christiane Stahl–Hennig∥,
Kerstin MätzRensing,
Dietmar Fuchs,
Jacek Skowroński,
Frank Kirchhoff
Publication year - 2000
Publication title -
journal of virology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.617
H-Index - 292
eISSN - 1070-6321
pISSN - 0022-538X
DOI - 10.1128/jvi.74.9.4155-4164.2000
Subject(s) - biology , simian immunodeficiency virus , tyrosine , proto oncogene tyrosine protein kinase src , phosphoprotein , sh3 domain , endocytic cycle , virology , mutation , tyrosine kinase , endocytosis , virus , microbiology and biotechnology , signal transduction , genetics , phosphorylation , receptor , biochemistry , gene
SIVmac Nef contains two N-terminal tyrosines that were proposed to be part of an SH2-ligand domain and/or a tyrosine-based endocytosis signal and a putative SH3-ligand domain (P104 xxP107 ). In the present study, we investigated the effects of combined mutations in these tyrosine and proline residues on simian immunodeficiency virus (SIV) Nef interactions with the cellular signal transduction and endocytic machinery. We found that mutation of Y28 F, Y39 F, P104 A, and P107 A (FFAA-Nef) had little effect on Nef functions such as the association with the cellular tyrosine kinase Src, downregulation of cell surface expression of CD4 and class I major histocompatibility complex, and enhancement of virion infectivity. However, mutations in the PxxP sequence reduced the ability of Nef to stimulate viral replication in primary lymphocytes. Three macaques infected with the SIVmac239 FFAA-Nef variant showed high viral loads during the acute phase of infection. Reversions in the mutated prolines were observed between 12 and 20 weeks postinfection. Importantly, reversion of A107 →P, which restored the ability of Nef to coprecipitate a 62-kDa phosphoprotein in in vitro kinase assays, did not precede the development of a high viral load. The Y28 /Y39 →F28 /F39 substitutions did not revert. In conclusion, mutations in both the tyrosine residues and the putative SH3 ligand domain apparently do not disrupt major aspects of SIV Nef function in vivo.