Multiple blocks to human immunodeficiency virus type 1 replication in rodent cells.

Area of Science:

• Virology
• Molecular Biology
• Genetics

Background:

• Human gene products are essential for early human immunodeficiency virus type 1 (HIV-1) replication.
• This suggests the potential for engineering rodents to support HIV-1 infection.

Purpose of the Study:

• To investigate the capacity of modified rodent cell lines (mouse, rat, hamster) to support productive HIV-1 replication.
• To identify specific blocks in the HIV-1 life cycle within these engineered cells.

Main Methods:

• Stable expression of permissive cyclin T1 in rodent cell lines to support Tat function.
• Analysis of HIV-1 replication steps including reverse transcription, integration, gene expression, virus entry, RNA processing, and virion assembly.
• Fusion experiments between rodent and human cells to assess the recessiveness of replication blocks.

Main Results:

• Engineered rodent cells supported early HIV-1 replication steps (reverse transcription, integration, early gene expression).
• Significant defects in CD4- and coreceptor-dependent virus entry, RNA processing, and Gag precursor processing were observed in mouse and rat cells.
• Hamster CHO cells showed fewer defects, producing infectious HIV-1 particles at levels closer to human cells.
• Blocks to infectious virus production in mouse and rat cells were found to be recessive.

Conclusions:

• Rodent cells engineered for Tat function can support initial HIV-1 replication stages.
• Posttranscriptional defects severely limit infectious HIV-1 production in most mouse and rat cells.
• Human gene products critical for HIV-1 virion morphogenesis are likely absent or nonfunctional in rodent cells.