Expression and processing of the AIDS virus reverse transcriptase in Escherichia coli

Area of Science:

• Virology
• Molecular Biology
• Biochemistry

Background:

• Pathogenic human viruses, like the acquired immune deficiency syndrome (AIDS) virus (human immunodeficiency virus), possess complex proteins difficult to study.
• Bacterial expression systems offer a viable method for producing viral proteins in sufficient quantities for detailed analysis.

Purpose of the Study:

• To express a segment of the AIDS virus pol gene in Escherichia coli.
• To investigate the production and processing of viral reverse transcriptase in a bacterial system.
• To determine if bacterial expression can mimic the proteolytic processing observed in human cells.

Main Methods:

• Gene expression of a pol gene segment from the AIDS virus in Escherichia coli.
• Assay of reverse transcriptase activity in bacterial cell extracts.
• Analysis of viral polypeptide formation and molecular weights.

Main Results:

• Expression of the pol gene segment led to detectable reverse transcriptase activity in bacterial extracts.
• Two virus-related polypeptides, p66 and p51, were identified with molecular weights matching mature virion-derived reverse transcriptase.
• Coexpression of sequences encoding a viral protease was necessary for the formation of these mature polypeptides.

Conclusions:

• The bacterial expression system successfully generated mature forms of AIDS virus reverse transcriptase.
• This system effectively mimics the proteolytic processing pathway occurring during human immunodeficiency virus infection.
• This bacterial system provides a valuable tool for studying AIDS virus proteins that are otherwise difficult to obtain.