MoLV reverse transcriptase polymerase

This chapter focuses on a few selected DNA polymerases that are most widely used in recombinant DNA technology. In the category of DNA-directed DNA polymerases (Section II), four DNA polymerases are described that originate from bacteria . coli and T. aquaticus) and bacteriophages (T4 and T7). In the category of RNA-directed DNA polymerases (Section III), two reverse transcriptases, one from AMV and the other from MoLV, are described. As the typical enzyme of template-independent DNA polymerases (Section IV), the terminal deoxynucleoti-dyltransferase (TDTase) from calf thymus is described. 

The reverse transcriptase (RTase) from the Moloney murine leukemia virus (MoLV) possesses both DNA polymerase and RNase (H and D) activities. It is monomeric (80 kDa) in solution but is presumed to function as a dimer. The ratio of the polymerase to RNase H activities and many of MoLV RTase functions are similar to those of AMV RTase. In contrast to AMV RTase, however, MoLV RTase does not possess DNA endonuclease activity. The gene for MoLV RTase has been cloned and expressed in . colt, and both wild-type RTase (RNase H" ) and modified RTase (RNase H ) are commercially available. MoLV RTase is thus a reliable reagent which shares with AMV RTase much of the role of cDNA synthesis in molecular cloning. Modified MoLV RTase has proven to be particularly useful in the synthesis of full-length cDNAs. 

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