Intracellular HIV-1 Gag localization is impaired by mutations in the nucleocapsid zinc fingers.
BACKGROUND
The HIV-1 nucleocapsid protein (NC) is formed of two CCHC zinc fingers flanked by highly basic regions. HIV-1 NC plays key roles in virus structure and replication via its nucleic acid binding and chaperoning properties. In fact, NC controls proviral DNA synthesis by reverse transcriptase (RT), gRNA dimerization and packaging, and virion assembly.


RESULTS
We previously reported a role for the first NC zinc finger in virion structure and replication 1. To investigate the role of both NC zinc fingers in intracellular Gag trafficking, and in virion assembly, we generated series of NC zinc fingers mutations. Results show that all Zinc finger mutations have a negative impact on virion biogenesis and maturation and rendered defective the mutant viruses. The NC zinc finger mutations caused an intracellular accumulation of Gag, which was found either diffuse in the cytoplasm or at the plasma membrane but not associated with endosomal membranes as for wild type Gag. Evidences are also provided showing that the intracellular interactions between NC-mutated Gag and the gRNA were impaired.


CONCLUSIONS
These results show that Gag oligomerization mediated by gRNA-NC interactions is required for correct Gag trafficking, and assembly in HIV-1 producing cells and the release of infectious viruses.
Grigorov
Boyan
B
LaboRetro, Unité de virologie humaine INSERM U758, IFR128, ENS, Lyon, France. boyan78@yahoo.com
Décimo
Didier
D
Smagulova
Fatima
F
Péchoux
Christine
C
Mougel
Marylène
M
Muriaux
Delphine
D
Darlix
Jean-Luc
JL
D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000737:chemistry; D003593:Cytoplasm / Q000737:chemistry; D011992:Endosomes / Q000737:chemistry; D015683:Gene Products, gag / Q000378:metabolism*; D016655:HIV Core Protein p24 / Q000235:genetics* / Q000378:metabolism*; D015497:HIV-1 / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D009154:Mutation; D011485:Protein Binding; D019065:Virus Assembly / Q000235:genetics; D016335:Zinc Fingers / Q000235:genetics*; D054301:gag Gene Products, Human Immunodeficiency Virus; D058727:RNA, Small Untranslated
D015683:Gene Products, gag; D016655:HIV Core Protein p24; D054301:gag Gene Products, Human Immunodeficiency Virus; C083868:gag protein p1, Human immunodeficiency virus; D058727:RNA, Small Untranslated