M-MLV Reverse Transcriptase (RT) is commonly used in the first step of RT-PCR as well as for primer extension experiments. In the presence of a single-stranded RNA or DNA template, primer, and deoxyribonucleotides, this enzyme will extend the oligonucleotide primer, producing a complementary strand.

Moloney Murine Leukemia Virus Reverse Transcriptase (M-MLV RT) is derived from a cloned region of the pol gene of M-MLV and isolated from an E. coli strain overexpressing this construct.