Reverse transcriptase reads through a 2'-5'linkage and a 2'-thiophosphate in a template

Area of Science:

• Molecular Biology
• Enzymology
• Virology

Background:

• Reverse transcriptases (RTs) are crucial enzymes in retroviral replication and molecular biology.
• RNase H activity of RTs is essential for processing RNA templates.
• Understanding RTs' interaction with modified RNA templates is vital for various applications.

Purpose of the Study:

• To investigate the pausing behavior of avian myeloblastosis virus (AMV) and Maloney murine leukemia virus (MMLV) RNase H-reverse transcriptases.
• To determine how these enzymes interact with specific RNA backbone modifications, including 2'-5' linkages and 2'-thiophosphates.
• To assess the implications of these pausing behaviors for interpreting primer extension assays.

Main Methods:

• Enzymatic assays using template RNAs with specific backbone modifications.
• Primer extension experiments with AMV and MMLV RNase H-reverse transcriptases.
• Analysis of pausing sites and read-through capabilities of the enzymes.

Main Results:

• Both AMV and MMLV RNase H-RTs exhibit pausing when encountering 2'-5' linkages or 2'-thiophosphates in RNA templates.
• Enzymes pause after the 2'-5' linkage but before the 2'-thiophosphate.
• Despite pausing, both enzymes eventually read through these modifications.

Conclusions:

• RNase H-reverse transcriptases show specific pausing behaviors at modified RNA sites.
• Primer extension data interpretation requires careful consideration of potential RT pausing at RNA lesions or non-standard linkages.
• Further studies are needed to characterize RTs' fidelity with diverse RNA modifications.