Visna-maedi virus reverse transcriptase (VMV RT)

Visna-maedi virus reverse transcriptase (VMV RT) is a critical enzyme produced by the Visna-maedi virus, a lentivirus that causes chronic, progressive inflammatory diseases in sheep, including pneumonia and encephalitis (PubMed: 11752710). As an RNA-directed DNA polymerase, VMV RT is responsible for transcribing the viral single-stranded RNA genome into double-stranded DNA, a necessary step for integration into the host cell genome (UniProt: P03362). The enzyme exhibits three distinct enzymatic activities: RNA-dependent DNA polymerase, DNA-dependent DNA polymerase, and RNase H (PubMed: 7513008). Because of its structural and functional similarities to the Human Immunodeficiency Virus (HIV) reverse transcriptase, VMV RT has served as an important model for studying lentiviral replication and testing antiretroviral drugs (PubMed: 2465466). It is primarily targeted by nucleoside reverse transcriptase inhibitors (NRTIs) like Zidovudine, which act as chain terminators to block viral replication. However, VMV RT often shows natural resistance to many non-nucleoside reverse transcriptase inhibitors (NNRTIs) designed for HIV-1, highlighting significant differences in their drug-binding pockets (PubMed: 8501671). Understanding the structure and function of VMV RT is essential for developing broad-spectrum antivirals and managing lentiviral infections in livestock.

Other names

Visna virus reverse transcriptaseVV RTRNA-directed DNA polymeraseReverse transcriptase (Visna-maedi virus)

Inhibition of viral DNA synthesis through competitive inhibition of the reverse transcriptase enzyme or premature chain termination during DNA polymerization.