Analysis of HIV type 1 reverse transcriptase expression in a human cell line

Area of Science:

• Molecular Biology
• Virology
• Biochemistry

Background:

• Human immunodeficiency virus type-1 (HIV-1) reverse transcriptase (RT) is a crucial enzyme for viral replication.
• HIV-1 RT is a heterodimer comprising p51 and p66 subunits, whose functional expression in host cells is complex.
• Previous attempts to express HIV-1 RT subunits in human cell lines faced challenges, particularly with HIV-1 protease expression.

Purpose of the Study:

• To analyze the functional expression of human immunodeficiency virus type-1 (HIV-1) reverse transcriptase (RT) subunits in a human cell line.
• To investigate the impact of HIV-1 protease (PR) on RT subunit expression and activity.
• To establish a human cell line constitutively expressing functional HIV-1 RT in the absence of viral infection.

Main Methods:

• Cloning and expression of HIV-1 RT and PR genes in the HT-1080 human fibrosarcoma cell line.
• Transient and stable expression systems were employed to analyze subunit production and RT activity.
• Immunofluorescence was used to determine the cellular localization of expressed RT subunits.

Main Results:

• Expression of the RT region alone yielded p66 but minimal RT activity.
• Co-expression of p51 and p66 subunits led to a significant increase in RT activity.
• Stable HT-1080 cells expressing both p51 and p66 showed a 15-fold increase in RT activity compared to controls.
• p51 subunit alone lacked detectable RT activity, highlighting the necessity of the heterodimer for function.

Conclusions:

• Constitutive expression of functional HIV-1 RT (p51/p66 heterodimer) is achievable in a human cell line without HIV-1 infection.
• The p51 subunit is essential for maximal RT activity, requiring co-expression with p66.
• This engineered cell line provides a valuable platform for studying HIV-1 RT function and developing antiviral strategies.