Cellular phenotype impacts human immunodeficiency virus type 1 viral protein R subcellular localization

Area of Science:

• Virology
• Cell Biology
• Immunology

Background:

• Human immunodeficiency virus type 1 (HIV-1) viral protein R (Vpr) is a regulatory protein crucial for the viral life cycle.
• Vpr is known to accumulate in the nucleus and at the nuclear envelope.
• Previous studies often overlooked cell types relevant to HIV-1 pathogenesis.

Purpose of the Study:

• To investigate how cellular phenotype impacts the intracellular localization of HIV-1 Vpr.
• To examine Vpr localization in cell lines representing key HIV-1 target cells in the peripheral blood, bone marrow, and CNS.

Main Methods:

• Used green fluorescent protein (GFP)-tagged Vpr to visualize its intracellular distribution.
• Analyzed Vpr localization in various cell lines including kidney, T lymphocyte, monocyte-macrophage, bone marrow progenitor, and astroglioma cells.

Main Results:

• In 293T cells, Vpr localized to the nucleus, nuclear envelope, nucleoli, and cytoplasm.
• In Jurkat T cells, Vpr was found in cytoplasmic speckles.
• In U-937 monocytic cells, Vpr accumulated intranuclearly; in TF-1 cells, it localized to the nuclear envelope and intranuclearly; in astroglioma cells, it showed perinuclear and cytoplasmic distribution.

Conclusions:

• Vpr localization is dependent on cellular phenotype, likely due to interactions with cell-specific host factors.
• These interactions may dictate Vpr's role in the viral life cycle within different cell types.
• Phenotype-specific Vpr localization could explain its secretion or release from infected cells in the peripheral blood and CNS.