Functional characteristics of a reverse transcriptase encoded by an endogenous retrovirus from Drosophila melanogaster

• Published in: Insect biochemistry and molecular biology 2005-04, Vol.35 (4), p.323-331
• Main Authors: Arnaud, F., Peyretaillade, E., Dastugue, B., Vaury, C.
• Format: Article
• Language: English
• Subjects: Animals; Base Sequence; cations; Cloning, Molecular; Dimerization; divalent cations; DNA - genetics; DNA Primers; Drosophila melanogaster; Drosophila melanogaster - virology; Endogenous retrovirus; enzyme activity; Errantivirus; functional domains; functional properties; genes; Kinetics; Life Sciences; pol gene; protein conformation; recombinant fusion proteins; Recombinant Fusion Proteins - metabolism; retrotransposons; Retroviridae - enzymology; Retroviridae - genetics; Retroviridae - isolation & purification; Retrovirus; Reverse transcriptase; RNA - genetics; RNA-directed DNA polymerase; RNA-Directed DNA Polymerase - genetics; RNA-Directed DNA Polymerase - metabolism; temperature; Thermodynamics; ZAM
• ISSN: 0965-1748; 1879-0240
• DOI: 10.1016/j.ibmb.2004.12.008

ZAM is an LTR-retrotransposon from Drosophila melanogaster that belongs to the genus errantivirus, viruses similar in structure and replication cycle to vertebrate retroviruses. A key component to its lifecycle is its reverse transcriptase which copies single-stranded genomic RNA into DNA. Here, we provide a detailed characterization of the enzymatic activities of the reverse transcriptase encoded by ZAM. When expressed in vitro, the reverse transcriptase domain associated with the RNase H domain encoded by the ZAM pol gene forms homodimers and displays an efficient RNA-dependent DNA-polymerase activity. It requires either Mg 2+ or Mn 2+ divalent cations, and works in basic pH, with a peak at around pH9. The so-called [RT-RH] polypeptide displays an optimal activity at 22 °C, a property that makes it well-adapted to the temperature of its host. This study contributes to our understanding of the general structures and functions of retroviral reverse transcriptases, a necessary process in the search for novel inhibitors.