TY - JOUR
T1 - Identification and characterization of virus assembly intermediate complexes in HIV-1-infected CD4+ T cells
AU - Lee, Young Min
AU - Yu, Xiao Fang
N1 - Funding Information:
We gratefully acknowledge the assistance of Dr. Michael Sayre (Department of Biochemistry) for column chromatography experiments. Many thanks are also given to Liza Dawson for the gifts of the ΔPOL and Pr− CD4+ T cell lines and helpful discussions and comments on the manuscript. This work was supported by Public Health Service Grants AI-35525 and DA-09541 from the National Institutes of Health.
Funding Information:
The fact that the DSC could be disrupted by nonionic detergent raises the possibility that its formation might be dependent on an association with lipid membrane. This possibility was supported by the results of experiments characterizing the formation of DRC and absence of DSC in a myristylation− mutant of HIV-1 Gag and Gag-Pol proteins. Although the DRC was readily detected in the CD4+ T cells and HeLa cells constitutively expressing unmyristylated Gag and Gag-Pol, the formation of DSC was not observed. It has been well established that myristylation of Gag molecules is required in most retroviruses including HIV-1 in order for tight membrane association of Gag molecules and formation of
PY - 1998/3/30
Y1 - 1998/3/30
N2 - For type-C and lentiviruses, including human immunodeficiency virus type 1 (HIV-1), the pathway of virus assembly remains poorly defined, and the assembly and budding of capsids are believed to occur simultaneously at the plasma membrane of the infected cell. We have now identified two putative HIV-1 assembly intermediate complexes in infected CD4+ T cells. The first of these intermediates, a detergent-resistant complex (DRC), was identified as a large oligomer that had a density of 1.10-1.13 g/ml and was primarily composed of Pr55(Gag) and Pr160(Gag-Pol) precursors. The other putative intermediate was a detergent-sensitive complex (DSC) with a density of 1.15- 1.17 g/ml, which apparently represented the products of extensive proteolytic processing of both the Pr55(Gag) and Pr160(Gag-Pol) precursors. Both complexes could be distinguished from released mature virions as well as immature viral particles. Surprisingly, the formation of DRC was not dependent upon the myristylation at the N-terminus of the Gag proteins, a signal required for plasma membrane targeting and virus production. However, the myristic acid modification was essential for the formation of DSC. These data suggest that interactions between individual Gag molecules and between Gag and Gag-Pol precursors may occur before their targeting to the plasma membrane during HIV-1 assembly. However, formation of the late virus assembly complex and productive processing of Pr55(Gag) and Pr160(Gag-Pol) precursors apparently do not occur until these precursors are targeted to the plasma membrane.
AB - For type-C and lentiviruses, including human immunodeficiency virus type 1 (HIV-1), the pathway of virus assembly remains poorly defined, and the assembly and budding of capsids are believed to occur simultaneously at the plasma membrane of the infected cell. We have now identified two putative HIV-1 assembly intermediate complexes in infected CD4+ T cells. The first of these intermediates, a detergent-resistant complex (DRC), was identified as a large oligomer that had a density of 1.10-1.13 g/ml and was primarily composed of Pr55(Gag) and Pr160(Gag-Pol) precursors. The other putative intermediate was a detergent-sensitive complex (DSC) with a density of 1.15- 1.17 g/ml, which apparently represented the products of extensive proteolytic processing of both the Pr55(Gag) and Pr160(Gag-Pol) precursors. Both complexes could be distinguished from released mature virions as well as immature viral particles. Surprisingly, the formation of DRC was not dependent upon the myristylation at the N-terminus of the Gag proteins, a signal required for plasma membrane targeting and virus production. However, the myristic acid modification was essential for the formation of DSC. These data suggest that interactions between individual Gag molecules and between Gag and Gag-Pol precursors may occur before their targeting to the plasma membrane during HIV-1 assembly. However, formation of the late virus assembly complex and productive processing of Pr55(Gag) and Pr160(Gag-Pol) precursors apparently do not occur until these precursors are targeted to the plasma membrane.
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U2 - 10.1006/viro.1998.9064
DO - 10.1006/viro.1998.9064
M3 - Article
C2 - 9527917
AN - SCOPUS:0032579806
SN - 0042-6822
VL - 243
SP - 78
EP - 93
JO - Virology
JF - Virology
IS - 1
ER -