RNase H domain mutations affect the interaction between Moloney murine leukemia virus reverse transcriptase and its...

Area of Science:

• Molecular Biology
• Virology
• Enzymology

Background:

• Moloney murine leukemia virus (M-MuLV) reverse transcriptase (RT) possesses distinct polymerase and nuclease active sites within a single polypeptide.
• Understanding the interplay between these domains is crucial for characterizing viral replication mechanisms.

Purpose of the Study:

• To investigate the impact of mutations in the RNase H domain of M-MuLV RT on its DNA polymerase activity and processivity.
• To examine the binding interactions between mutant RTs and primer-template DNA, focusing on potential dimerization.

Main Methods:

• Site-directed mutagenesis was employed to introduce specific alterations in the RNase H domain of M-MuLV RT.
• DNA synthesis processivity assays were conducted using the mutant and wild-type RTs.
• Complex formation between primer-templates and RTs was analyzed to assess dimerization.

Main Results:

• Mutant M-MuLV RTs with alterations in the RNase H domain exhibited significantly decreased processivity in DNA synthesis.
• While M-MuLV RT is monomeric in solution, it binds primer-template DNA as a dimer.
• Several mutants with reduced DNA synthesis processivity failed to form this characteristic RT-DNA dimer.

Conclusions:

• The RNase H domain plays a critical role in maintaining the processivity of M-MuLV RT DNA polymerase activity.
• Proper dimerization of M-MuLV RT with primer-template DNA is essential for efficient DNA synthesis.
• Mutations affecting the RNase H domain can disrupt dimer formation, leading to impaired polymerase function.